Sách Giáo Khoa Về Lột Da Hóa Học (Chemical Peels – Ấn Bản 2)

342      Textbook of Chemical Peels
(c)
(a)
(d)
(b)
Figure 37.30  (a) Lentigines before Only Touch. (b) Only Touch applied too deeply: frosting has turned buff-yellow. The contact time
between the applicator and the skin was too long. (c) Prolonged erythema (6 weeks), abnormal after Only Touch: the contact time between
the applicator and the skin was too long. (d) Three months after treatment: almost complete resolution of erythematous spots and no PIH.
Lentigines have gone.

Complications of chemical peels      343
Prevention
Proper Patient Selection
Sensitivity Test  If the patient has a history of PIH, a sensi-
tivity test could be conducted on a hidden area. It is worth
bearing in mind that if the test is negative, patients will be
convinced that they are safe from complications and it is far
more likely that any problem that might arise will be attrib-
uted to the practitioner’s presumed incompetence rather than
any particular skin sensitivity. Different areas of the face do
not react to peels in the same way: a patch test behind the
ear does not really say anything about how the area around
the mouth will react. Sensitivity tests should therefore be seen
more as a means of dissuading a patient who is likely to have
complications rather than a means of preparing for any poten-
tial problems. A patient with a ­pigmentary reaction to a test
should be ruled out for treatment with medium or deep peels
and be oriented toward a peel that causes less melanocyte
stimulation.
Genetic Factors  The capacity to develop PIH is largely depen-
dent on genetic factors. Patients who suffer from pigmentary
changes after a peel often develop hyperpigmentation from
insect bites or small operative scars, and it is worth questioning
patients before starting treatment.
Skin Phototype  The risk of pigmentary changes increases
with the skin phototype: as a general rule, Fitzpatrick skin
types I–III develop little or no hyperpigmentation and are
therefore excellent candidates for deep peels. The lighter and
more even the complexion, the fewer problems there will be
with pigmentary changes. The darker the skin, the greater the
risk of pigmentary changes. Phototypes IV–V rapidly develop
hyperpigmentation after any inflammation, even without sun
exposure. A medium-depth peel (to the papillary dermis) on a
dark skin phototype should always be preceded by skin prepa-
ration. These treatments will not stop all PIH, however. It is
therefore wise only to perform less aggressive peels on patients
with a dark skin type. Asian patients and patients whose geno-
type does not correspond to phenotype24 are more susceptible
to PIH.
Preparing the Skin
Prevention of Infections  If there is any history, no matter how
transient, of herpes, valaciclovir should be prescribed (two
times 500 mg/day before and after the peel). In principle, her-
pes outbreaks do not leave scars, but they can sometimes leave
some localized pigmentation for months or even years. To avoid
secondary infections, medium or deep peels should not be per-
formed during infectious outbreaks of acne.25
Cleansing and Degreasing the Skin  If the skin is not cleansed
and degreased evenly or not properly prepared before a TCA–
SAS peel, the acid can penetrate unevenly and PIH may occur.
Organic matter inactivates the acids,26 and the presence of lip-
ids or surface debris can alter the depth of penetration. Easy
TCA solution was designed not to be affected by the presence
of this surface organic debris. It is a saponified solution of TCA
that is applied without prior degreasing and cleansing.
Overcleansing should be avoided. The skin must not be
mechanically abraded when disinfecting and degreasing; the
stratum corneum must not be destroyed by overenthusiastic
wiping.27 This manual abrasion would be uneven and create
areas of deeper penetration, increasing the risk of scarring and
pigmentation.
The pressure applied when cleaning the skin should be
firm and, above all, even.
Even Application of the Peel
AHAs  AHAs must be applied quickly; if they are applied
slowly, the areas treated first should also be the first areas to be
neutralized. Partial and gradual neutralization is difficult and a
source of errors. AHAs should therefore be applied as quickly as
possible, starting with the most resistant areas, such as the fore-
head. If the acid is applied quickly, all areas can be considered
to have had almost the same contact time and the whole face
can be neutralized at once. The whole treatment area should
be monitored extremely closely to make sure that the peel is
neutralized as quickly as possible if it is about to penetrate too
deeply in any specific area.
TCA–SAS  The more force applied on the applicator, the
more deeply the TCA will penetrate. Applying TCA with a
brush gives a more superficial peel than applying the same
concentration with a gauze pad. The number of coats must
be the same all over: the depth of the peel increases with the
successive number of coats of TCA applied. At a constant con-
centration, three coats of TCA produce a deeper peel than two
coats.
The concentration of the TCA must also be taken
into account: with the same number of coats, a more highly
Figure 37.31  Unexpected pigmentary change after a full-face
phenol peel. Note also the inadequate results.

344      Textbook of Chemical Peels
concentrated TCA will give a deeper peel. It is important
to watch out for any teardrops that may dilute the TCA and
its action. Tear tracks on the cheeks can leave a line of more
superficial penetration. Tears can also carry TCA onto the neck,
where it can produce an unwanted linear peel together with
PIH.
Easy TCA  The ease of application and weekly repetition of
this peel guarantee even results and an almost complete lack of
PIH, if Easy TCA is applied to pinpoint frosting.
Only Touch  For information on the application of Only Touch,
see the earlier discussion in this chapter and Chapter 22.
Phenol  Phenol must be applied evenly. The depth of the peel
depends on the number of coats and the type of solution used.
Chapter 34 describes in detail the application methods needed
to get an even result. It is extremely important to follow the
application methods for each particular formula carefully. In
all cases, any occlusive mask must be even and not form “bub-
bles” or areas of pressure. Any tears could carry phenol onto
the neck (linear peel and increased probability of PIH).
Sun Avoidance and Protection
The sun is not the only cause of postpeel hyperchromia. Rubin14
describes coming across cases of hyperpigmentation where
there has been no sun exposure. For more information on sun
protection, see Chapter 3.
Medicines and Pigmentation
Some medicines can cause pigmentation. These include estro-
gens and progestins (including oral contraceptives), phenothi-
azines, thyroid hormones, and photosensitizers, among others.
Close Monitoring
Pigmentation disorders (as well as scars) are often preceded by
persistent localized erythema that must be treated as quickly as
possible (see earlier discussion). Again, the patient should have
an overall treatment program. The patient does not come just
for a peel but to improve his or her skin. The practitioner is not
being asked for a treatment but for a result, especially one that
does not damage the skin. Patients should be seen as often as
required. Generally, the deeper the peel, the more frequent the
checkups should be. A phenol peel, for example, requires daily
monitoring for the first 8–10 days after treatment. Over the first
few days after a TCA peel to the basal layer of the epidermis or
the Grenz zone, a pseudo-pigmentary change can be seen to
appear (Figure 37.32) that results from dehydration of the epi-
dermal layers where melanin is found. Acids bind readily with
water molecules and dehydrate the skin. The melanin gran-
ules are brought closer together and the skin appears darker in
places.28 It is not possible for a genuine pigmentary change to
set in within 2 or 3 days.
Prevention through Re-Peeling
TCA–SAS  Fouque and Seban29 limit pigmentary changes by
automatically applying an AHA peel after a TCA in aqueous
solution. Although AHAs are not toxic to melanocytes, these
superficial peels can—partially or completely—put a stop to
any pigmentary changes that are common between the 2nd and
4th week following a TCA peel in aqueous solution, especially
in countries with very sunny climates. The protocol includes
three phases:
•
First phase: The patient applies a depigmenting cream for
the first 2 weeks after the peel with TCA–SAS.
•
Second phase: Three weeks after the aqueous TCA, a
50% buffered glycolic acid peel is done to test the skin’s
sensitivity.
•
Third phase: The following week a 70% unbuffered peel is
applied for 1 minute, then neutralized.
As soon as the condition of the skin permits, a peel to
the basal layer of the epidermis can be envisaged to reduce
the quantity of intraepidermal melanin and improve the pen-
etration and action of depigmenting agents. Any additional
inflammation must, of course, be avoided, as this would cre-
ate a second wave of hyperpigmentation. The author uses only
Easy TCA to treat pigmentary changes: application of the peel
solution to the start of pinpoint frosting and application of the
postpeel mask cream, whose main properties are antioxidant,
tyrosinase-inhibiting, and anti-inflammatory.
Easy TCA  If there is a pigmentary change after one session of
Easy TCA, the next session will “stop it in its tracks” and treat it.
Pregnancy  Cortez30 relates that if a patient becomes pregnant
in the first few months after a phenol peel, dyschromia disor-
ders may occur. Pregnancy is contraindicated in the months
following a deep peel, especially in patients with a high risk of
pigmentary changes.
Treatment
If prevention fails, treatment must follow. The more superficial
the pigmentation, the better will it respond to treatment. If the
hyperpigmentation originates in the dermis, it will not respond
as well to treatment. It is often necessary to treat the actual
inflammation that is maintaining the pigmentation.
Examining the skin under a Wood’s lamp (354  nm)—
also called “black light”—can help determine the depth of the
lesions. The more pigmented the skin appears in the Wood’s
light, the more superficial the pigmentation. The angle of the
light should be varied to improve the visual accuracy of the
Figure 37.32  Pseudo-hyperpigmentation of the forehead: photo-
graph taken on the 4th day after a Unideep peel to the papillary
dermis. The skin has started to flake above the left eyebrow.

Complications of chemical peels      345
diagnosis. Skin that looks washed out by the Wood’s light will
not respond well to depigmenting treatment.31
Whatever the case may be, the author’s first choice of
treatment for epidermal or dermal postpeel PIH is always four
sessions of Easy TCA to the basal layer (pinpoint frosting) in
combination with Blending Bleaching Cream. Results can often
be seen after the first re-peel.
Topical Depigmenting Agents
Monobenzone  Monobenzone (Figure  37.33), also known as
monobenzyl hydroquinone, benoquin, and hydroquinone
monobenzyl ether, has a molecular weight of 200.27 and is a
stable chemical compound under normal conditions. It is not a
new depigmenting molecule: the Journal of the American Medical
Association published an article about it in 1956.32 Monobenzone
is used to completely inhibit the production of melanin from
tyrosine, mainly in certain severe cases of vitiligo. However,
it is rare to resort to this rather extreme treatment. Doctors
are, in fact, more willing to use techniques for repigmenting
areas of vitiligo than techniques for complete depigmentation
of normally pigmented areas.33 Monobenzone34 should only be
applied after attempts at repigmentation have failed and when
the vitiligo makes social life difficult. Patients with severe vitil-
igo are happy to be one color again. However, the cosmetic risks
are high: the skin becomes completely white, burns in the sun,
and any hope of normal repigmentation, if for example a cure
for vitiligo were discovered, vanishes as soon as monobenzone
is applied. This product should never be used as a simple whit-
ening agent, at any concentration.
In any event, complete depigmentation usually only
develops after 6 months to 4 years, with three daily applica-
tions, and the depigmentation protocol, which is very precise,
is full of pitfalls.35 The patient must also be aware that there
can be permanent and complete depigmentation in areas other
than those being treated; the hair can go gray, but the eyes do
not change color. Nevertheless, 11 of 15 vitiligo patients treated
with monobenzone developed conjunctival melanosis, and one
patient had a line of corneal pigment deposit in each eye after
one year of monobenzone.36
Monobenzone can cause contact allergies37 that, oddly
enough, occur mainly on areas of normal color skin and
very rarely on the vitiligo patches. Fifteen percent of patients
develop skin rashes. Sun protection must be worn permanently,
as the skin loses all its melanin protection.
Depigmentation does not occur systematically, and some
patients who respond well at first do less well later on. Others
regain pigmentation in patches over the summer months. A few
rare vitiligo patients repigment, sometimes fairly evenly, with-
out the underlying mechanism being understood, when mono-
benzone is stopped and they no longer need to depigment.
Nevertheless, there are still some monobenzone depig-
menting creams on the market: they have low concentrations
of monobenzone (around 1.5%). Nevertheless, some highly
concentrated means at 20% can be found on the market. When
applied to the hands, there have been cases of permanent,
­confetti-like depigmentation that has spread to the forearms.38
Monobenzone is therefore not indicated in the treatment
of freckles, melasma, age spots, PIH, and other ­dyschromias,
apart from cases of severe vitiligo that resists attempts at
repigmentation.
Other Topical Depigmenting Agents  Conventional topical depig-
menting agents (hydroquinone, kojic acid, Morus alba, arbu-
tin, azelaic acid, lactic acid, etc.) do not destroy the melanin
in the skin, but inhibit tyrosinase and the oxidative stages of
the chemical reactions that turn tyrosine (Figure  37.34) into
indole groups during the first stages of melanogenesis. AHAs,
retinoic acid, salicylic acid, and so forth, increase flaking and
eliminate the intraepidermal melanin stock more quickly.
Corticosteroids and  nonsteroidal anti-inflammatory agents
combat inflammation.
Topical depigmenting agents cannot be expected to pro-
duce rapid results: the active products have to penetrate the
skin and change the metabolism of the melanocytes, reduc-
ing ­melanogenesis or changing the quality of the melanin.39
A ­completely new epidermis then has to be built from cell growth
in the basal layer, which takes 4–6 weeks. Depigmentation is
therefore gradual, and topical depigmenting agents are often
combined with products that accelerate epidermal flaking.
Hydroquinone  Hydroquinone is closely related to phenol and
can reduce melanin production. It appears that it can also
degrade melanosomes. It has a tyrosinase-inhibiting activity
and can change the membrane structure of the intracellular
organelles of ­melanocytes. Hydroquinone acts mostly on the
first stages of melanin synthesis. Its action is therefore gradual,
like any tyrosinase inhibitor.
Is it worth using preventively? Applying hydroquinone
creams during the weeks before a peel reduces melanin synthe-
sis, and the patient will slowly see a certain improvement in the
hyperpigmentation, depending on how long and how potent
the treatment is. However, it is not certain that the preventive
HO
O
Figure 37.33  Monobenzone.
OH
COOH
NH2
Figure 37.34  Tyrosine. Note the resemblance to the usual tyrosi-
nase inhibitors.

346      Textbook of Chemical Peels
application of hydroquinone before a peel can reduce the reac-
tive potential of melanocytes during inflammation. The author
never applies hydroquinone before a peel for two main rea-
sons: first because of the problems associated with hydroqui-
none itself, which will be considered later in this chapter, and
second because of its low anti-inflammatory potential. On the
other hand, it can be advantageous to use hydroquinone after
a peel to inhibit melanin synthesis. It should be applied as soon
as possible after the peel, during the reepithelialization stage. It
can therefore be applied immediately after a glycolic acid peel
or Easy Phytic Solution,40 5–7 days after a peel to the papillary
dermis,41 and 8–10 days after a peel to the reticular dermis. The
concentration normally used is between 2% and 6%. It should
be noted that European legislation limited hydroquinone to 2%
in cosmetic products for many years and finally banned it alto-
gether. Concentrations of less than 4% hydroquinone are less
effective. Concentrations higher than 4% are more effective but
also more irritating.
It takes several months to achieve an acceptable clinical
result when hydroquinone is used as monotherapy, but abnor-
mal epidermal and dermal pigmentation can eventually be
reduced. There are reports in the literature that hydroquinone
has been prescribed in high doses (up to 10%–15%) to counter
dramatic pigmentary changes; at these doses, it must not be
applied for more than 8 days and a more conventional concen-
tration of 3%–5% should be used for the rest of the ­treatment.
The effect is dose-dependent, and it might be concluded that
a high concentration is always required to get a rapid and
­clinically satisfactory result. However, it is important to bear
in mind the problems that have been associated with the use
of this agent:
•
Its action is due to its cytotoxic effect.
•
Hydroquinone is irritating to the skin.
•
It can cause ochronosis:42 the patient soon develops a
blue-black patch that is not easy to treat. Ochronosis can
appear even if the patient has not had a peel beforehand.
Ochronosis usually appears after concentrations higher
than 4% have been applied, but lower concentrations can
cause it in patients with Fitzpatrick skin type V or VI.
•
It can cause confetti-like depigmentation.
•
It is potentially mutagenic.
Hydroquinone has also been combined with other
­molecules to increase its penetration and effectiveness, as in
the Kligman formulas:
•
Kligman’s original triple-combination formula:43
Hydroquinone powder, 5%
Dexamethasone powder, 0.1%
Tretinoin powder, 0.1%
Hydrophilic ung, qs ad 60 g
•
Kligman’s four-ingredient formula:
Hydroquinone, 2.5 g
Tretinoin, 0.05%
Ascorbic acid, 0.1 g
Dexamethasone acetate, 0.05 g
Eucerin O/W, ad 50 g
(or natural unguent La Roche–Posay ad 50 g)
in an opaque tube
Other depigmenting formulas can be prescribed:
Tretinoin, 0.1%
Hydroquinone, 4% ana
(+ triamcinolone acetonide to combat inflammation if desired)
Use twice daily until the local problem is resolved.30
Rubin,14 quite rightly, highly recommends the following,
less irritating formulation:
Glycolic acid, 10%
Hydroquinone, 4%
Substituting 0.1% tretinoin with 10% glycolic acid
removes an irritant and potentially photosensitizing factor
while enhancing penetration and therefore the effectiveness of
hydroquinone.
Lower concentrations have been tested successfully. Their
synergy means that the concentrations of each active product
can be reduced and hence their side effects are also reduced.
The formula is as follows:14
Citric acid, 3%
Lactic acid, 3%
Hydroquinone, 2%
Kojic acid, 2%
Many prescription formulas have been developed,
­combining, for example, vitamin C and indomethacin:
Hydroquinone, 5%
Tretinoin, 0.025%
Vitamin C, 0.2%
Dexamethasone acetate, 0.01%
Indomethacin, 2%
Cream O/W, ad 30 g
All of these hydroquinone creams are still fairly irritat-
ing to the skin, and many commercial formulations have been
developed with new cosmeceutical technologies that are not
available in pharmacies.44
Finally, it should be noted that hydroquinone poses a
serious galenical problem, as it tends to oxidize quickly: prepa-
rations containing hydroquinone have to be mixed and pack-
aged in an oxygen-free atmosphere (in nitrogen). Preparations
packaged in jars oxidize too quickly and lose most of their
effectiveness within a few days. The ideal packaging for
hydroquinone cream is a hermetically sealed, double-layer,
aluminum tube.
Kojic Acid  Kojic acid (Figure 37.35), also known as 5-hydroxy-2-
(hydroxy-methyl)-4H-pyran-4-one and 5-hydroxy-2-(hydroxy­
methyl)-1,4-pyrone, is a tyrosinase inhibitor (through copper
chelation and caseinase inhibition). It has been isolated from
Aspergillus, Acetobacter, and Pencillium species. It has antibacte-
rial properties and reduces the production of free radicals (iron
chelation). It has been used since 1988 (Japan) as a bleaching
agent, for both the skin and teeth and in the food industry. It
also has antiseptic and antioxidant properties. Kojic acid is
more stable and better tolerated than hydroquinone, but pro-
longed use has caused contact dermatitis, especially on Asian
skin types. It is usually used in doses of 2%–4%. It can be

Complications of chemical peels      347
combined with glycolic acid and enhances the penetration and
action of the latter. The toxicity of kojic acid has been tested
in mice: oral administration produced thyroid follicular adeno-
mas. Kojic acid is a strong goitrogen in rodents, lowering blood
concentrations in thyroid hormones and stimulating thyroid-
stimulating hormone (TSH). As a result, the thyroid gland
increases in volume and weight and there is diffuse thyroid
follicular hypertrophy/hyperplasia.
Azelaic Acid  Azelaic acid (Figure 37.36), also known as non-
anedioic acid, 1-7-heptanedicarboxylic acid, anchoic acid, lep-
argylic acid, and azelainic acid, has a molecular weight of
188.22, which limits its penetration through the skin. Azelaic
acid is therefore more effective when it is combined with other
molecules that can enhance its penetration (AHA, retinoids,
etc.). It has antibacterial45 properties used in the treatment of
acne or rosacea. At doses of 20% (Skinoren), azelaic acid has
tyrosinase-inhibiting properties46 through competition. Even
though its tyrosinase-inhibiting activity is not as strong as that
of hydroquinone, it is useful for treating melasma or PIH. It
reduces DNA synthesis in hyperproliferating melanocytes in
hyperpigmentation. Unfortunately, it is slow-acting (several
months) and has little effect on old PIH and on deep, dermal
pigmentation. Azelaic acid does not act on normal melanocytes
or fibroblasts and does not cause leukodermia or ochronosis.
Tests on animals show that azelaic acid is not cytotoxic, muta-
genic, or teratogenic.47,48
Glabridin, Licorice Extract  Glabridin (Figure 37.37) is the most
active depigmenting component of licorice extract. It has an
inhibiting action on melanogenesis, without affecting mela-
nocyte DNA or RNA synthesis. It is therefore not cytotoxic.
Glabridin 0.5% inhibits erythema and UVB-induced pigmen-
tation. It also has anti-inflammatory properties through the
inhibition of superoxide anion production and through cyclo-
oxygenase activity.49 It is therefore a good indication in the
treatment of PIH.
Arbutin  The arbutin molecule (Figure 37.38) consists of hydro-
quinone labeled to glucose, and is also known as hydroquinone-
ß-d-glucopyranoside. It mainly works by inhibiting tyrosinase
activity rather than suppressing the synthesis or expression
of this enzyme. Apparently, arbutin does not hydrolyze to
release hydroquinone, which is not therefore directly respon-
sible for the inhibition of melanin synthesis.50 Nevertheless, it
has not been officially proved to have a strong depigmenting
effect, and one study shows that applying arbutin can increase
pigmentation.51
4-Hydroxyanisole (4-HA)  4-HA is a cytotoxic molecule that
inhibits melanogenesis (at 2%) but only seems to be effective
when combined with tretinoin (at 0.01%). Used alone, it appears
not to be active.
Vitamin E (α-Tocopherol)  Vitamin E (α-tocopherol; Figure 37.39)
is one of the best antioxidants for cell and organelle mem-
branes. It stabilizes and prevents the destruction of the lipids
that make up these membranes, which are very susceptible to
oxidation. It blocks the chain reactions that cause intracellular
OH
O
O
OH
Figure 37.35  Kojic acid.
O
OH
OH
O
Figure 37.36  Azelaic acid.
O
O
H
HO
OH
Figure 37.37  Glabridin.
OH
O
OH
OH
HO
HO
O
Figure 37.38  Arbutin.

348      Textbook of Chemical Peels
lipoperoxides to form, thus protecting the nucleic acids and
proteins. It also inhibits the peroxidation of membrane arachi-
donic acid, which prevents the subsequent formation of pro-
inflammatory prostaglandins.
Vitamin E has a beneficial antioxidant effect during the
postpeel period. One single molecule of vitamin E protects
3000 membrane phospholipids. Stabilization of the lysosome
membranes prevents the release of histamine, which reduces
the duration of solar erythema.
Vitamin E has other actions:
•
Protection of the superoxide dismutase (SOD) enzyme that
neutralizes superoxide radicals.
•
Limitation of the formation of links that make the collagen
protein chains rigid.
•
Limitation of the production of malonedialdehyde, whose
action on the glycation of proteins is linked to the aging
process.
•
Acceleration of the healing of burns.
Japanese publications report that vitamin E can be used
effectively in the treatment of facial pigmentation. It inhibits
tyrosinase indirectly by inhibiting its hydroxylase activity. It
also acts by limiting the oxidative phases required in the first
stages of the transformation of tyrosine into indole derivatives.
Vitamin E oxidizes easily, and more stable derivatives than
pure α -tocopherol have to be used in cosmetic preparations.
Tocopheryl acetate is one of the more stable derivatives of vita-
min E. Tocopheryl ferulate is also frequently used.
Vitamin A (Retinol)  It has been proved that vitamin A (reti-
nol; Figure 37.40) and its analogs,52 used in topical applications,
enhance skin regeneration by increasing the rate of keratino-
cyte division. Retinol induces cell differentiation in the basal
layer of the ­epidermis and enhances apoptosis of old cells,
which in turn facilitates the regeneration of healthy keratino-
cytes. Retinol controls cell migration in the skin epithelium;
this migration is an essential stage in skin regeneration. Many
different mechanisms of action have been suggested: one is
that the retinol acts as a signal that facilitates the interaction
of epidermal growth factor (EGF) with the cells of the skin
epithelium. Retinol also modulates the transcription of cer-
tain genes. Many other effects have been attributed to retinol
in topical application. It is a hydrating molecule that increases
the thickness of the epidermis through selective multiplication
of living ­keratinocytes at the expense of the keratinocytes that
make up the stratum corneum. Because the stratum corneum
is thinner, the skin appears softer and more hydrated. Retinol
also prevents the formation of ­comedonal acne by preventing
corneocytes from building up in the outlets of the piloseba-
ceous units and forming plugs. Retinol counters PIH by accel-
erating ­keratinocyte turnover, which helps eliminate epidermal
melanin more quickly. Topical retinoic acid (tretinoin) has a
well-known ­irritant effect, due to the fact that it builds up in
places where it does not exist naturally in these concentrations.
Pure, encapsulated retinol in cyclodextrins can be an effective
replacement. In fact, pure retinol penetrates more readily than
its palmitate or acetate esters. Pure, encapsulated retinol in
cyclodextrin reaches the deep layers of the skin in a few hours
and arrives at its target without being oxidized. Bearing in
mind the stages of retinoic acid synthesis in the skin, it is clearly
worthwhile to use retinol.
Retinoic acid is synthesized inside keratinocytes. The
retinol is first converted into retinal (retinaldehyde), which is
in turn converted into retinoic acid. Both of these stages are
enzyme-dependent.
Retinoic acid regulates the transcription of genes that
code for the synthesis of important intracellular proteins.
Retinol also induces the expression of the protein that trans-
ports retinoic acid. Retinol encapsulated in cyclodextrins
(Renutriv ACE Lipoic Complex from Skin Tech) has greater
­bioavailability and its antioxidant action is of better quality.
Vitamin C (L-Ascorbic Acid)  Vitamin C (L-ascorbic acid;
Figure 37.41) can limit melanin ­production, as it has a tyros-
inase-inhibiting and antioxidant activity. Skin cells naturally
use ascorbic acid in energy metabolism and when synthesiz-
ing collagen. A deficiency in vitamin C is a well-known cause
of many disorders, including ­hyperkeratotic folliculitis and
delayed wound healing.
Ascorbic acid is unstable in aqueous solution and is not
liposoluble. It oxidizes rapidly, losing its protective properties,
and more stable derivatives are generally used. Magnesium
ascorbyl phosphate is one of the most stable and hydrophilic
vitamin C derivatives. On the surface and inside the skin, it
is rapidly converted into vitamin C by a phosphatase enzyme
found in abundance both on and inside the skin. Magnesium
ascorbyl phosphate is a more effective antioxidant and longer
HO
O
Figure 37.39  Vitamin E (α-tocopherol).
OH
Figure 37.40  Vitamin A (retinol).
HO
P
OH
O
O
O
O
HO
HO
OH
Figure 37.41  Vitamin C (l-ascorbic acid), in the form of ascorbyl
phosphate.

Complications of chemical peels      349
lasting than the derivative ascorbyl palmitate, often used in
topical preparations. This is because the enediol function53 of
the second carbon atom of ascorbyl phosphate is protected,
while the palmitate derivative has no protection for this area
of the molecule, which is responsible for the acid and antioxi-
dant properties of vitamin C. Magnesium ascorbyl phosphate
can be used on the most sensitive skins, such as skin that has
just benefited from a peel. It is readily absorbed by the topical
route and lasts for a long time inside the skin, which gives it a
sustained tyrosinase-inhibiting action and therefore a lighten-
ing and depigmenting effect. Topical vitamin C (Purascorbol
aesthetic dermal) also has an antiaging effect that works in dif-
ferent ways:
•
It modulates the three genes responsible for the synthesis
of procollagen leading to an increase in type III collagen
synthesis. This action is very important for postpeel heal-
ing and maintaining normal skin structure.
•
It is a cofactor of prolyl and lysyl hydroxylase enzymes in
the first stages of collagen synthesis; these are necessary
for the inclusion of proline in collagen.
•
It takes part in elastin synthesis.
•
The antioxidant effect of vitamin C provides protection
against the harmful effects of UV rays.
•
It protects vitamin A from oxidation and prevents protein
chains from breaking.
•
It has a protective action on other antioxidant systems,
which is beneficial in situations where free-radical produc-
tion is increased (e.g., during postpeel oxidative stress).
This is also the case with infected or uninfected wounds
and areas exfoliated by peels or other abrasive or resurfac-
ing techniques.
•
It enhances reepithelialization.
Morus Alba (Mulberry or White Mulberry) Extracts  Mulberroside
F (also known as 3′-di-O-α-d-glucopyranoside and moracin
M-6), extracted from mulberry leaves, inhibits tyrosinase activ-
ity, in the conversion of dopa (3,4-dihydroxy-α-phenylalanine)
into dopachrome (dopa oxidase activity). This tyrosinase-
inhibiting activity has been measured as 4.5 times more
powerful than that of kojic acid.54 Mulberroside F also has an
antioxidant activity on the superoxide anion.
AHAs  The melanogenesis-inhibiting properties of lactic
acid and glycolic acid have been shown55,56 in the treatment of
melasma as well as solar lentigines and PIH. The mechanism
of action lies not only in the faster dispersion of pigments in a
more rapidly renewed epidermis, but also in the inhibition of
tyrosinase activity. This inhibition has no relation to the acid-
ity of these products, as studies show that tyrosinase-inhibiting
activity is constant, even below pH 5.6.
Important Observations on the Use of Topical Depigmenting
Agents  One of the explanations for the failure of depigment-
ing treatments is that they are often applied extremely locally,
to the hyperpigmentation itself, whereas they should be applied
evenly to the whole face in the morning, for example, and again
in the evening on the hyperpigmentation alone.
Sun Avoidance
Complete sun avoidance can by itself resolve many hyperpig-
mentation problems within 6–18 months. See also Chapter 3.
Local Corticosteroids
When a peel causes localized inflammation that visibly devel-
ops into hyperpigmentation, even with sun protection and
avoidance, a corticosteroid (preferably a fluoro-corticosteroid)
should be applied. It should be applied twice a day locally to
the erythema before it develops into hyperpigmentation and
should not be used long term (1 week at the most), to avoid
the side effects associated with corticosteroids. This treatment
should be combined with sun protection/avoidance measures
and a topical depigmenting agent.
SCARRING
Unlike pigmentation problems that are common after many
peels, scarring is fortunately a rare complication. Some areas of
the face are more sensitive. Scars can arise directly from exces-
sively deep, chemical destruction of the dermis57 or can be the
“logical” result of neglecting a sign—for example, ignoring and
not treating persistent erythema properly. Treatment needs to
start as soon as possible: as soon as scarring seems likely, as a
stabilized scar is unfortunately a permanent scar.
The deeper the peel, the more effective it is, but also the
more dangerous. A deep peel, when performed correctly, pro-
duces exceptional results in the majority of cases. The author
has never come across any report of complete facial necro-
sis after a peel. Fortunately, therefore, the problem remains
­localized. Scarring can be atrophic, hypertrophic, or retractile,
depending on the depth of the burn and the area treated. To
have a better understanding of the risk of postpeel scarring, we
must review the physiology of skin healing.
Brief Chronology of Healing
Initial Phenomena
The process starts almost immediately: neutrophils enter
the treated area during the peel and stay there for 3–5 days.
Macrophages are present from day 3 to day 10 and lymphocytes
from day 6 or 7.
Reepithelialization
This starts 24 hours after the peel and begins with centripe-
tal keratinocyte migration followed by accelerated cell prolif-
eration. It should be effective within a week—that is, protect
(­partially, as there is only one layer of cells) the dermis.
Collagen Regeneration
After reepithelialization, dermal collagen is regenerated over a
2- to 3-month period.
Various Facts about Postpeel Healing
Open healing is slower than when the reepithelializing wound
is covered. This does not matter for intraepidermal peels, as the
dermis is still covered by several layers of living and protective
keratinocytes. On the other hand, when it comes to medium or
deep peels,58 this is of major importance. Peels have an advan-
tage over laser or mechanical abrasive treatments in that they
leave a layer of skin in place. This layer of skin is of course
dead, but it offers protection against external aggressions and
enhances reepithelialization. The strips of skin that survive
after a medium or deep peel should therefore be left in place, as
they protect the regenerating skin. Lasers gradually vaporize
the layers of skin to be eliminated, and if it were not for colloid
dressings, the skin would have to heal in the open. The colloid
dressings on the market (Convatec, Omniderm, Vigilon, etc.)

350      Textbook of Chemical Peels
allow better-quality healing in a moist environment after laser
treatment. Totally occlusive dressings (including Vaseline)
carry an increased risk of infection and have to be monitored
actively, as bacteria proliferate far more rapidly under occlusion
than in the open air. Because of the increased bacterial prolifer-
ation and the skin’s lowered immune defenses after a medium
or deep peel,59 it is preferable to use a moist healing method
after a phenol peel. A mask of bismuth subgallate or thymol
iodide is used for this after a phenol peel (see Chapter 35).
Postpeel hydration is also important. The skin should
not be allowed to dry out while it is reepithelializing after a
medium or superficial peel; it needs to be hydrated. Proper
hydration prevents pruritus and delayed healing.60 Hydration
after a deep peel is essential after the first week.
Sterile white Vaseline is an excellent topical that can be
applied to treated areas:
•
During the first few days after a peel to the papillary
­dermis.
•
After the healing mask has been removed (from the 7th–
8th day) after a phenol peel.
Only a thin layer of Vaseline need be applied to prevent
any pruritus triggered by surface keratinocytes (that have not
yet differentiated into corneocytes) from drying out. Vaseline
creates an impermeable layer on the surface of the skin and
prevents water from evaporating from the epidermis (TEWL:
transepidermal water loss). Water accumulates under the layer
of Vaseline and provides immediate natural hydration that
soon relieves the pruritus caused by the keratinocytes drying
out. Patients on whom Vaseline is applied should be monitored
particularly closely because of the increased risk of secondary
infection under occlusion. Aloe vera extracts appear to accel-
erate healing after dermabrasion but have the disadvantage
of potentially causing contact allergies. The use of antioxidant
creams may also be indicated during the first few weeks after a
peel (Renutriv ACE Lipoic Complex from Skin Tech).
Risk of Scarring Depending on the Molecule Used
AHAs
When an AHA peel is strictly intraepidermal,61 the risk of scar-
ring is nonexistent, as there is no phenotypic conversion of
fibroblasts into myofibroblasts (see discussion earlier in this
chapter). In the 1990s, when the use of AHAs in cosmetic medi-
cine first took off, women’s magazines carried reports of real
disasters with gruesome photographs. A popular German mag-
azine62 (Brigitte, 19/95: 62–8) told the story of a journalist who,
out of professional conscientiousness (or curiosity?), decided
to test a peel of 70% glycolic acid in simple aqueous solution
in a reputable cosmetic surgery clinic. After a few months of
preparation with tretinoin,63 the doctor quickly applied several
coats of 70% glycolic acid and left his nurse to take charge of the
immediate follow-up. According to the journalist, the peel was
not neutralized but simply rinsed with water64 several times,
even though the patient complained of persistent burning. The
eyes also had to be rinsed, as the copious amounts of water
used on the face had carried the acid into the conjunctival cul-
de-sacs. The patient went home, and the doctor left on vacation
the same day. The next day, alarmed by the condition of her
skin, the patient wanted to see the doctor and, as her surgeon
was away, saw one of his colleagues, who was of course horri-
fied to see that a product as strong as an AHA at 70% had been
applied on such lovely skin. The danger was so great that he
had to prescribe manual lymphatic drainage. Other colleagues
told the patient that “it would last for years.”
The article goes on to say that three months later, the
patient was still dealing with some after-effects, but it fails to
describe the state of the skin, and the results of a single AHA
peel obviously is little. The journalist concluded that she would
never again let herself be treated with any acid whatsoever,
given the “daily horror” she had to live through after trying the
lightest one. This is confirmation that a thorough knowledge
of the techniques, together with a high degree of professional
conscientiousness, is essential to avoid problems and that any
peel, even a superficial one, can cause complications.
TCA
Publications often present this molecule as being the most
likely to penetrate too deeply and cause scars. Books and jour-
nals about peels are full of photographs of complications and
scars resulting from peels with TCA–SAS (Figures  37.42 and
37.43).7 According to Litton7 and Stone,65 “deep” TCA has a natu-
ral tendency to cause hypertrophic scars. In reality, it must be
used in accordance with precise rules, and practitioners must
be aware of and respect its symptomatology. TCA should never
leave any scars.
The risk of scarring after a TCA peel is linked to the acid
penetrating too deeply.
The total quantity of TCA applied to the skin during a
peel determines the depth of the peel. This quantity depends on
(among other things) the concentration of the solution and the
number of coats applied. Applying a highly concentrated TCA
peel means that a lot of acid goes into the skin at once and it is
impossible to control the depth. The more concentrated the TCA
is, the more deeply it penetrates. One of the major problems
stems from the fact that the concentration is calculated in differ-
ent ways in different parts of the world: although percentages
are always given, a concentration in mass per mass (m/m) is
not the same as in mass per volume (m/v) or mass plus volume
(m+v).66 The m/m concentration is the strongest.
At equal concentrations, the more coats that are applied,
the deeper the peel, as each coat that is applied soaks the skin in
a little more TCA, which will combine with more proteins and
destroy other cells.
The risk of scarring is also linked to the thickness of
the skin. The thinner the skin, the more deeply the TCA
will penetrate; the thicker the skin, the less it will penetrate.
Nevertheless, scars do not only form where the skin is thinnest.
On the contrary, they can also form in areas where the skin
is thicker, with areas of thin skin remaining scar-free. These
“paradoxical” scars can often be explained by an intentionally
“forceful” application on an area that is mistakenly believed to
be more resistant and in an attempt to get better results.
Dry skin allows TCA to penetrate more rapidly and more
deeply than hydrated or oily skin, which is usually thicker than
dry skin. Skin lipids deactivate TCA, and well-hydrated skin
dilutes it. TCA that penetrates well-hydrated skin encounters
more water than it does when it penetrates dry skin. The more
aggressively the skin is prepared, the more permeable it will
be and the TCA will penetrate more rapidly: caution must be
observed with regard to prepeel degreasing and disinfecting,
which abrade the skin and are not recommended for all peels.
Patients should be questioned before a peel to find out if they
regularly use products on their skin that reduce the thickness
or impermeability of the stratum corneum (AHAs, tretinoin,
benzoyl peroxide, salicylic acid, etc.).

Complications of chemical peels      351
The type of applicator also plays a role in determining
the depth of penetration of the acid: gauze abrades the skin as
the acid is applied and promotes quicker and deeper penetra-
tion, while a brush spreads the TCA on the stratum corneum
without enhancing penetration and therefore produces a more
superficial peel.
TCA penetrates more readily where the skin has been
damaged. TCA–SAS should therefore not be applied imme-
diately after hair removal, coagulation of telangiectasias, a
­session of mesotherapy, filling wrinkles, and other treatments.
Easy TCA is not a simple aqueous solution of TCA but rather a
“tamed” solution that can be applied safely after the treatments
listed above. An aqueous solution of TCA is unstable; a tamed
solution67 is far more stable and penetrates more evenly.
The risk of scarring after a TCA peel is also linked to
the quality of the care surrounding it. Apart from some seri-
ous cases, scars do not form immediately but are preceded by
prolonged local erythema and/or infection that should be diag-
nosed and treated appropriately. Many problems (see those
­discussed later in this chapter) can be avoided by proper patient
selection, and postpeel monitoring can limit others.
Scars usually—but not always—occur in patients with
dry and thin skin who have been treated with too much TCA–
SAS of an inappropriate concentration or quality and for whom
monitoring and postpeel care have been neglected or inad-
equate. They can also occur in patients with thicker skin who
have a history of hypertrophic scars.
Phenol
It is reported that, at the same depth of injury, phenol causes
fewer problems with scarring than TCA.68 According to Fintsi,69
the Exoderm formulation is “self-blocking”: it somehow recog-
nizes the reticular dermis and stops its action there. Other new
(a)
(b)
Figure 37.42  (a, b) A scar probably due to uneven application of TCA–SAS, 50% m/m.
Figure 37.43  Scarring after TCA in aqueous solution of unknown
concentration: probably 50% m/m.

352      Textbook of Chemical Peels
formulations (e.g., Lip & Eyelid) have this advantage. Although
some phenol peels with rather exotic or inappropriate proto-
cols have produced scar reactions, certain current phenol peel
formulations are less aggressive, kinder to the skin, and just as
effective. The fact that the phenol automatically stops acting at
the reticular dermis should be treated with caution: it cannot
be safely assumed that a phenol formula will stop in every case
right at the most superficial part of the reticular dermis, even
if technically phenol is self-blocking, as it neutralizes itself by
combining with proteins. We still do not know at which depth
it is completely neutralized. “Self-blocking” also depends on
the total amount that was applied in the skin.
General Prevention of Scarring
Patient Selection
Special care should be taken with patients who have extremely
thin, dry, or sun-damaged skin, as the acids penetrate this very
permeable skin more quickly and more deeply and the skin
can sometimes overreact. Careful anamnesis will reveal any
personal or family history of keloids or any tendency to scar
hypertrophy. Insulin-dependent diabetics should be ruled out
from a peel to the reticular dermis (because of the increased
risk of scarring and infection), whereas diabetic patients (type
2, non-insulin-dependent) who are stabilized on oral antidia-
betic drugs can have a deep peel on condition that they are
monitored more closely than usual.
Ehlers–Danlos Syndrome
It would be more appropriate to talk of Ehlers–Danlos syn-
dromes,70 as this is a heterogeneous group of connective ­tissue
disorders, a “diffuse hereditary”71 disease, of which to date 10
groups and different subgroups have been identified. Paganini
is suspected to have suffered from it.72 Types I–IV and type VIII
can be diagnosed clinically, while types VI, VII, IX, and X require
laboratory diagnosis.73 The different subgroups are character-
ized by deficiencies at different levels: there are mutations of
genes coding for type I or III collagen or for certain enzymes.70,74
In certain subgroups (VIIC), electron microscopy shows that
the collagen is laid down in sheets rather than fibrils and takes
on a hieroglyphic pattern.75 The incomplete or light forms of
the syndrome are certainly more common than reported in the
literature71 and some authors suggest a worldwide incidence of
9% of the population.68 It typically manifests as fragility and
hyperelasticity of the skin and joint hypermobility. The skin
can be stretched further than normal skin and returns to its
original state when let go. Minor ­traumas cause disproportion-
ate loss of substance and atrophic, parchment-thin scarring. The
skin eventually loses its elasticity, and its appearance resembles
“cutis laxa”—loose, hanging, and wrinkled.
From a clinical point of view, the coexistence of at least
two of the following symptoms should arouse suspicion:76
•
Skin hyperelasticity.
•
Joint hyperlaxity.
•
Frequent bruising.
•
Atrophic scars or pseudotumors.
•
Calcified subcutaneous cysts.
•
Family history of the syndrome.
A depressed nasal pyramid and prominent paranasal
folds change facial morphology; the skin is hyperelastic and
can sometimes hang on the face.77 It is especially important to
be aware of this syndrome and try to detect borderline cases
in patients wanting rejuvenating techniques. Surgeons should
be particularly wary because of the possibly fatal vascular
complications.78,79
Treatment with Isotretinoin
Patients who have used isotretinoin (13-cis-retinoic acid,
Accutane) or other more recent retinoids during the previous
year or are going to use it within the next 12 months should be
ruled out from medium or deep peels. Some authors even sug-
gest leaving a gap of 2–3 years between isotretinoin and a peel,
as this product:
•
Destroys the sebaceous appendages.
•
Inhibits the expression of collagenase.
•
Inhibits procollagen production.
•
Inhibits cell growth and delays wound healing.
Delayed reepithelialization exposes the damaged skin
to mechanical injury as much as physical injury and infection,
and there is a risk of hypertrophic, star-shaped scars on the
cheeks that can form months after a peel has been carried out
too soon after isotretinoin.
Patients whose skin has been significantly changed by
isotretinoin and who still complain of dry or fragile skin should
not be given any type of peel.80 It is absolutely vital to wait for
the skin to heal completely with restitutio ad integrum before per-
forming any kind of peel, even if it takes years. Common sense
dictates that it is better to live a few more years with wrinkles
than live the rest of one’s life with scars. Intraepidermal peels
or peels to the basal layer theoretically do not pose such a seri-
ous risk, as regeneration does not rely on the fibroblasts or skin
appendages. The problem in this case lies in increased skin per-
meability, which could deepen the action of the acids. AHAs
and TCA in aqueous solution should be considered likely to
cause scarring in combination with isotretinoin.
Skin Preparation
Skin preparation must be even, suitable to the skin type and
not excessive. Some peels are only really effective after several
weeks’ of skin preparation (TCA–SAS), whereas for other prod-
ucts (Exoderm, Easy TCA, and Lip & Eyelid) prepeel prepara-
tion is pointless, and in some cases any prepeel preparation is
contraindicated (Easy Phytic82).
If preparation is too rough, the skin will be too perme-
able to the acids—overall and locally. Results might sometimes
be better, of course, but if preparation is too aggressive, the
safety factor is reduced. It is essential to follow the instructions
provided with each formulation and each technique. They are
based on the experience and errors of their authors and help
avoid pitfalls and accidents.
Avoiding Injuries
•
Except in cases where the doctor wishes to increase the
depth of peel penetration intentionally,83 patients must be
warned not to use “exfoliating scrubs” on their skin dur-
ing the days before a peel. If the patient uses an exfoliat-
ing scrub, or a “home peel,” as it is known for marketing
purposes, it may be uneven and enhance penetration of the
acid locally.
•
Secondary infections must be avoided: close postpeel
monitoring is necessary.
•
Premature re-peeling should be avoided: a re-peel should
not be done if reepithelialization is not complete.

Complications of chemical peels      353
•
A full-face deep peel should not be done at the same time
as a face-lift; however, it is possible to do a chemical cheilo-
plasty84 or a chemical blepharoplasty at the same time as a
surgical face-lift, for example.
•
Scratch lesions should be avoided.
Persistent Localized Erythema
As we have seen earlier in this chapter, persistent localized ery-
thema (especially in high-risk areas) is more often than not a
sign of dyschromia rather than scarring. Indurated erythema
poses a risk of scarring more than PIH.
Specific Prevention Depending on Peel Type
AHAs
AHA peels are superficial peels that do not have a natural
tendency to cause scarring. If the doctor himself monitors
the peel and the neutralization stage as usual, in principle
there is no chance of scars forming. If the peel is neutralized
as soon as erythema appears, there is no risk of scarring.
A  peel that is ­neutralized too late, however, can cause scar-
ring. Neutralization (acid + base) should not be confused with
­dilution (acid + water). Dilution is not always enough: the rec-
ommendations given in the protocol for each particular prod-
uct must be followed.
Easy Phytic Solution
Easy Phytic Solution (see Chapter 11) is a slow-release and
self-neutralizing mixture of fruit acids and phytic acid (pH
<1). The peel solution can only be applied on an intact stratum
corneum, where it will concentrate and gradually be released.
The gradual penetration of the acids does not overwhelm the
skin’s buffer capacity.85 Any prior treatment likely to acceler-
ate or increase penetration of the acids could overwhelm the
skin’s buffer capacity and cause problems. There have been no
reports of scarring to date, and Easy Phytic can be considered
extremely safe as far as scarring is concerned.
TCA–SAS
TCA penetrates very rapidly through the skin. If it penetrates
too deeply, it is often too late before it is noticed, and surface
neutralization is not enough to reverse the caustic, scarring
processes triggered deep down. In reality, TCA is only partially
neutralized, even if base solutions are applied immediately:
only the excess TCA on the skin surface can be neutralized. In
high-risk areas or on thin and permeable skin, it is therefore
recommended to use lower concentrations of TCA and to apply
the product less vigorously (choice of applicator). Care should
be taken to avoid any inadvertent drips of TCA86 or the acid
stagnating in the base of deep wrinkles: there is a risk of lin-
ear overpeeling, traces of which can remain visible for many
months or even be permanent in cases of large excesses. Scars
can be avoided by not using TCA to reach the reticular dermis,
apart from focal treatments (Only Touch).
Easy TCA
Easy TCA consists of a base solution and a postpeel cream.
A specific quantity of TCA in aqueous solution at 50% m/m
must be added to the base solution to activate it. Using the basic
protocol (i.e., to pinpoint frosting only) prevents any risk of
scarring, as the peel only reaches the basal layer of the epider-
mis. Moreover, applying the postpeel cream limits or stops the
immediate postpeel inflammatory reaction. If the application
procedure is followed correctly, there is no risk of overpeeling
and no risk of scarring. Care should be taken not to use the
aqueous solution of TCA 50% m/m as it is, without mixing it
with the adjuvant, base solution. There is no doubt that apply-
ing an aqueous solution of TCA 50% m/m directly to the skin
carries a high risk of scarring.
This error has been made several times,87 but if the doctor
follows the recommended application technique, he will notice
that with 50% m/m TCA, an unusually intense and rapid frost-
ing appears on the forehead and the patient will feel an intense
pain; the doctor will stop the application before starting to treat
the more sensitive areas of skin, where the risk of scarring is
greater. As discussed previously, the skin on the forehead is
more resistant to chemical injury. If this wrong concentration
is used, applying plenty of Easy TCA postpeel cream imme-
diately after washing the skin with copious amounts of water
will limit the injury and prevent serious complications in the
majority of cases.
Only Touch
Only Touch consists of a base solution whose qualitative for-
mula is based on that of Easy TCA and to which a specific quan-
tity of TCA in aqueous solution at 80% m/m must be added.
The 80% aqueous solution, which is very aggressive, cannot
be applied directly to the skin at the risk of penetrating too
deeply and causing permanent scarring. Following the appli-
cation procedure is absolutely essential: Only Touch is dabbed
quickly88 on lentigines and keratoses of less than 1 cm in diam-
eter. Treating larger areas rapidly increases the risk of scarring.
It is easy to avoid scarring if the following rules are
observed:
•
Be careful not to apply 80% m/m TCA directly to the skin.
•
Touch the area to be treated quickly and precisely.
•
Achieve pure white frosting and not gray-white.
•
Avoid any excess solution (drips, runs).
•
Monitor any persistent erythema and treat it.
Phenol
Phenol solutions must be prepared rigorously; any small varia-
tion in preparation causes unwanted local or systemic effects.
Baker–Gordon solution is unstable. Applying phases of
different concentrations to different areas of the face can be
avoided by shaking the solution constantly throughout the
whole peel procedure and keeping the solution homogeneous.
If the solution is not shaken, it can produce an uneven peel:
undertreated areas will be next to overpeeled areas, where
scars might form. For this reason, it is preferable to use formu-
las that remain homogeneous (Lip & Eyelid). When an occlusive
mask is used, it should be applied evenly, without air bubbles
or excessive pressure:
•
If there are air bubbles in the occlusive dressing, the phe-
nol cannot macerate evenly and some areas will be under-
treated, whereas if the occlusive mask is too tight, scars can
form where the severe edema that develops in the first few
hours after a phenol peel causes too much local pressure.
•
The occlusive mask does not usually go under the jaw, as
the movements and traction to which the dressing will be
subjected will cause the same phenomenon as described
above.
•
The patient must be closely monitored, as bacterial, viral,
or fungal infections can develop unnoticed over the days
after a phenol peel.

354      Textbook of Chemical Peels
•
Any pruritus should be treated to avoid scratch lesions, a
source of scarring.
•
The application protocol recommended with one type of
peel formula cannot necessarily be used with another.
Nevertheless, although phenol is a deep peel, it does not
cause scarring as readily as TCA at the same depth.
•
Applying Vaseline as occlusion after phenol is just as effec-
tive as a dressing and does not carry the risk of air bubbles
or areas of pressure. However, Vaseline increases the risk of
infection and rules out any touch-up the day after the peel.
Treating Scars
•
It is better to prevent scars than treat them.
•
The results will be better if treatment is started quickly.
•
It is a mistake not to aggressively treat developing scars.
Ectropion
The first case of ectropion after a peel was described in 1984,89
and surgical correction was successful. No doubt there are
other previous cases that have not been published or of which
the author is not aware.
Severe cases have also been reported90 after eyelid peels;
however, ectropion is not a specific complication of deep eyelid
peels.
Ectropion can also be a complication of the following:
•
Surgical treatment: It is in fact the most common complica-
tion after surgical blepharoplasty. Particular care should
be taken when doing a peel if the patient has a history
of blepharoplasty and even more so in cases of multiple
blepharoplasties. Patients with lagophthalmia should in
principle be ruled out from deep peels, although some
cases can be treated cautiously.
•
Various cosmetic treatments: Ectropion can occur after deep
peels with TCA or phenol and after laser treatment or
mechanical abrasion.
•
Systemic medication: 5-fluorouracil (5-FU) by the systemic
route can cause ectropion. A case of ectropion that occurred
after topical application of 5% 5-FU has been described.91
The complication was bilateral and resolved when treat-
ment was stopped.
•
Topical treatments: The appearance of ectropion after long-
term treatment with tretinoin has been described. In this
case, it is reversible when treatment stops.
Prevention of Ectropion
If ectropion seems to be developing:
•
A flexible silicone dressing that will resist the pull of the
scar should be applied (Figure 37.44).
•
A strong corticosteroid should be rubbed gently and slowly
into the affected area.
•
Corticosteroid injections in situ may prove effective.
Prevention and Treatment of Scars
Strong, topical corticosteroids should be applied, twice daily,
very locally. A self-adherent silicone dressing (Silastic or
Mepiform/Mepitel;92 Figure 37.44) should be worn 24 hours a
day that adapts to the curves of the skin and does not pull away
growing cells when the dressing is changed.
Corticosteroids (e.g., Celestone–Depomedrol) can be infil-
trated. The injection technique is important:
•
Location: The corticosteroids must be injected into the scar
tissue itself and not in the tissue surrounding the scar. Not
only is an injection underneath or beside the scar ineffec-
tive, it can also cause fat atrophy underneath or beside the
scar that would make it more obvious.
•
Frequency: Two injections should be given per month, with
gradually increasing doses until the scar goes away. The
scar should become soft and non-adherent. Scars often
respond well to this treatment within 1 month.
If no treatment seems to be working and the scar is
­permanent, there are a few solutions:
•
Surgical excision combined with a preventive silicone pres-
sure dressing to avoid local recurrences; as for ectropion,
Litton and Trinidad7 recommend simply waiting for a few
months instead of rapid surgical excision.
•
Laser treatment.
•
Concealing with special camouflage make-up (e.g.,
Covermark®).
(b)
(a)
Figure 37.44  Silicone sheets: (a) Mepiform. (b) Mepitel.

Complications of chemical peels      355
The prognosis is much better if the scar results from over-
peeling (technical error) rather than the nature of the skin itself
(e.g., with Ehlers–Danlos syndrome). A technical error can be
attributed to experience, and there is no reason why it should
happen again during a repeat peel. If the scarring results from
the patient’s genetic make up, she or he should not be given
another peel.
SECONDARY INFECTIONS
Skin that has just been treated with a peel93 is more prone to all
types of infection, as it can no longer rely on its different defense
mechanisms being intact. The risk mainly depends on the depth
of the peel and how carefully it is applied. However, other fac-
tors come into play. Secondary infections rarely cause major
problems, and do not really leave scars if treatment is started
in time. Infections are most often local, but can become general-
ized in some serious cases or after a peel to the reticular dermis.
Risk of Infection Depending on Peel Type
Peel to the Epidermis and Basal Layer:94 Very Low Risk
One of the skin’s defenses against infection is “neutralized”
by all peels: the destruction of the stratum corneum makes
the skin more permeable to microorganisms. The cells of the
stratum disjunctum—the outermost cells in normal skin—are
shed regularly and take with them a large amount of microbial
fauna. This desquamation, which is a natural drainage route for
the skin, cannot take place immediately after a peel, as the epi-
dermis tends to keep its cells in order to regain its normal thick-
ness and form a physical barrier to microorganisms. Without
regular desquamation, microorganisms that have managed
to penetrate through the skin’s first line of defense cannot be
physically eliminated.
The majority of the skin’s immune defenses are found
in the deep layers of the epidermis and dermis. An intraepi-
dermal peel lets in many xenobiotic microorganisms, but all
of the skin’s defenses remain viable and usually stop any local
infection from developing. After an intraepidermal peel, skin
regeneration is very rapid and there is not really enough time
for infection to set in. Intraepidermal peels are usually repeated
once a week or every 2 weeks. Each intraepidermal peel stim-
ulates the skin’s regenerative capacities, and the skin finds it
easier and easier to resist infection. Therefore, these peels do
not increase the risk of infection (or increase it just slightly). The
risk of herpes is not increased.
Peel to the Grenz Zone:95 Fairly Low Risk
The risk of infection increases with the depth of action of
the acids. The absence of the stratum corneum explains the
increased penetration of microorganisms; the destruction of
many of the skin’s immune defenses gives more freedom to
microorganisms to grow. However, the epidermal barrier is
still partially effective;96 the dermal barrier is completely active
and even stimulated.
Apart from scratch lesions that can develop into very
localized infections, a peel to the Grenz zone is not particu-
larly dangerous as far as infection is concerned. If an infection
should develop after a peel to this depth, a topical antibiotic is
usually enough to control it.
Easy TCA applied to pinpoint or cloudy-white frost-
ing causes virtually no infections, apart from a few potential
­transient infections of scratch lesions (the frequency is approxi-
mately 1 in a 1000).
Peel to the Papillary Dermis:97 Significant Risk
The acid puts the majority of the skin’s immune defenses out
of action. The doors are wide open to microorganisms (there
is no stratum corneum or epidermis): they are no longer elimi-
nated by the continual shedding of dead cells, and the immune
system cannot fight against them. The acids have burned the
Langerhans cells and other defenses in the papillary dermis,
and the skin is waiting for its immune defenses to be renewed.
The risk of infection is significantly higher than with a peel to
the Grenz zone. It is essential to take all necessary precautions
to avoid, prevent, and/or treat any infection.
Peel to the Reticular Dermis:98 Very Significant Risk
The skin no longer has any physical or immune defenses, and is
at the mercy of any microbe attack. The patient’s health depends
entirely on the hygiene measures taken during the peel and on
the quality of postpeel care.
Secondary infections can be local, loco-regional, or gen-
eral. They can be bacterial, fungal, or viral.
Secondary Bacterial Infections
Local and Loco-Regional Bacterial Infections
Local and loco-regional infections occur in cases of local
overpeeling99 above all or after scratch lesions (Figure 37.45).
Although peels to the papillary or reticular dermis are more
likely to become infected, infections can nevertheless develop
after a more superficial peel.
Fortunately, serious local infections are rare, as the peel-
ing agents, especially phenol, are germicidal.100 Moreover,
the skin on the face is rich in blood vessels and has effective
defenses against infections. With age, however, there are fewer
blood vessels in the face and the skin becomes more susceptible
to external aggression. Infections seem to develop more readily
and are more serious when peels are performed in a hospital
setting, because of the presence of multiresistant strains. The
author is fortunate not to have any dramatic photos of post-
peel infections to show, but many cases of secondary infec-
tion and scratch lesions from streptococci, staphylococci, and
Pseudomonas have been described in the literature.68 Following
Figure 37.45  Secondary infection: scratch lesions after Easy
TCA.

356      Textbook of Chemical Peels
the rules will allow the practitioner to perform secure peelings
with a very low infection rate.
Pruritus must be treated rapidly to prevent infections.
Deep peels, to the reticular dermis, obviously pose a particular
risk of secondary infection during the first week after treatment.
Conventional care often includes the application of an
antibiotic cream or ointment. This local antibiotic cannot be
applied in superimposed layers, and patients should wash their
skin before applying a new layer of antibiotic. Cleaning the skin
is a problem in itself, as it may injure the extremely sensitive
skin and is often painful. As a result, patients do not always
clean their skin before each new application, and put one layer
of ointment on top of another. After a few days of maceration,
it is almost inevitable that a secondary infection will develop.
Other patients clean the skin too vigorously before each
application of antibiotic: the regenerating skin gets damaged,
severe inflammation is maintained, and secondary infec-
tions develop more readily. The antibiotic ointment should
therefore be cleaned off carefully and evenly, using a show-
erhead to gently spray tepid water directly onto the skin. The
skin can be degreased with a gentle cleansing lotion before
showering.
Using a “powder mask” (bismuth subgallate or thymol
iodide) during the first week after a peel to the reticular dermis
(Lip & Eyelid) limits or even prevents secondary infections—
not only because of the properties of the powder itself, but also
because the patients have absolutely nothing to do themselves:
they will not have to touch the skin directly and therefore can-
not import any infectious agents (Figure  37.46). The powder
protects the skin from external aggression and from micro-
organisms in particular long enough (6–7 days) for the skin’s
defenses to be sufficiently restored by the time the powder
mask is removed. The author has never come across any infec-
tion when using this “dry” technique, while small infections
often have occurred when using antibiotic creams.
General Bacterial Infections: Toxic Infections
A few cases of toxic shock were reported after facial peels with
Baker’s solution in 1982, 1983, and 1987 and after rhinoplasty
in 1983. Todd and colleagues described the first cases of toxic
shock syndrome in 1978 as a result of the use of certain tam-
pons. It appears to be caused by an enterotoxin F and/or exo-
toxin C with the same molecular weight (22 000), secreted by
Staphylococcus aureus. Other authors suspect that the two toxins
are really one and the same.101
Symptoms  The
following
symptoms
should
alert
the
practitioner:
•
A temperature higher than 39°C in the first 2–4 days after a
medium or deep facial peel; the patient’s temperature may,
however, rise slightly and innocuously (37–38°C maxi-
mum) in the first 12 hours after the peel.
In cases of toxic shock, other symptoms follow the rise in
temperature:
•
Skin rash.
•
Low blood pressure (systolic <90 mmHg).
•
Vomiting and diarrhea.
•
Muscle pain.
•
Mucous membrane infection.
•
Kidney damage.
•
Liver damage.
•
Hematological problems (anemia or thrombocytopenia).
•
Damage to the central nervous system.
Treatment  Treatment is aggressive and requires hospitaliza-
tion. Patients should be taken to the hospital as soon as there
is any suspicion of toxic shock (raised temperature) and before
any other symptoms appear. The symptoms of infection are
often hard to spot: there was no visible sign of infection beneath the
thymol iodide powder before the start of toxic shock described
in the 1980s after a phenol peel (Baker’s solution). Toxic shock
syndrome can come like a bolt from the blue. In the cases
described, the skin recovered normally and no scars were left
after recovery.
Prevention of Bacterial Infections
Intraepidermal peels to the basal layer or the Grenz zone do
not require such stringent precautions as deep peels, and treat-
ment can be monitored as normal. There should be no particu-
lar problem with infection with this type of peel.
Deeper peels require more attention.
General Precautions for Deep Peels
•
A basic precaution is surgical sterilization of everything
that comes into contact with the patient.
•
Any staff members with a microbial infection should be
kept out of direct contact with the patient and, if they have
ear, nose, or throat (ENT) infections, should wear a mask.
•
Patients should be ruled out from treatment if:
•
they have an active infection in the area to be treated
with a deep or medium peel,102
•
they have an ENT infection,
•
they have insulin-dependent diabetes, or
•
they are immunodeficient.
The peel solution is usually applied with a swab or cotton
buds. The skin should never be touched with the bare hands
during or after the peel.
Figure 37.46  Protective mask of bismuth subgallate powder after
treatment of wrinkles on the upper lip with Lip & Eyelid Formula.

Complications of chemical peels      357
Special Precautions for Phenol Peels
The phenol solution is “rolled”103 onto the skin with a cotton
bud soaked in the product. If the doctor makes the applica-
tor himself, he should check that his hands are sterile before-
hand. It is difficult to make this rolling movement with gloved
hands, as the glove can wind around the applicator and make
application awkward, or even dangerous. Only the left hand
should be gloved, and the right hand should be surgically
disinfected and not come into contact unnecessarily with the
skin.
Infections are more common with the “moist”104 healing
technique than with the “dry”105 technique.
The drawback to using creams when the epidermis is
regenerating is that skin debris builds up and forms a base
for the infection underneath the occlusive layer. The advan-
tage, however, is that it is possible to see how the epidermis is
progressing during the first week, which is not possible with
an occlusive mask of thymol or bismuth. If practitioners pre-
fer the “moist” technique, they should prescribe an antibiotic
cream, preferably without corticosteroids, and bear in mind
the possibility of contact allergies. Patients have to wash their
skin under a showerhead four times a day to get rid of the skin
debris and then apply a new layer of antibiotic cream (e.g., baci-
tracin). Special care must be taken not to damage the growing
epithelium. Not cleaning the skin properly has led to alarm-
ing secondary infections from Pseudomonas,106 in the form of
­pyoderma. Proper debridement and cleaning together with
appropriate antibiotic treatment stop this infection.
Treating Bacterial Infections
It is enough to proceed logically: topical or systemic antibiotic
treatment should be used. A bacteriological sample should be
taken before any treatment to make a culture and an antibio-
gram. Treatment should start before the results of the culture
arrive.
Small, Localized Infection
If the patient does not have a fever, he or she should be treated
with local antibiotics.
In the particular case of phenol used in combination with
a “dry” healing technique, topical antibiotics can be applied
directly onto the powder mask. The powder will come away
(not a serious consequence), and the epidermis will be laid bare.
A “moist” technique should then be used locally.
Loco-Regional Bacterial Infection
Figure 37.47 shows a case of loco-regional infection beginning
at the end of the occlusive regeneration phase of a full-face
­phenol peel. The patient did not have a fever but had numerous
painless, papular lesions on the neck. Oral antibiotic treatment
cleared up the problem in a few days.
Postpeel Acneiform Dermatitis
Postpeel acneiform dermatitis occurs readily under a greasy
“dressing” (e.g., Vaseline) and should be treated with oral
­antibiotics. It clears up in 6–8 days.
Suspected Toxic Shock
The patient should be hospitalized immediately.
Secondary Herpes Infections
Secondary herpes infections are very widespread,107 and the
risk of “waking up” the virus is very real, especially for peels to
the papillary dermis.
Risk Depending on Peel Type
Peel to the Epidermis or Basal Layer  The risk of herpes activa-
tion is minimal.108 The skin is not badly injured and its defenses
are still strong enough. AHA, Easy Phytic, or Easy TCA peels
can therefore be performed—no further than the basal layer—­
without any fear of a herpes outbreak.
Peel to the Grenz Zone  Depending on how prone the patient is
to herpes, valaciclovir can be used to prevent it. Patients who
say they have only had one outbreak of herpes, “20 years ago,”
can quite reasonably be treated without any herpes prevention
if the peel does not go beyond the Grenz zone (Easy TCA—
cloudy frosting), but they should still be closely monitored.
Patients who say they suffer from herpes “all the time and at
the drop of a hat” should, of course, automatically receive her-
pes prevention.
Peel to the Papillary or Reticular Dermis  A person who has had
even just one outbreak of labial herpes in their life is at serious
risk of a recurrence in the days following a peel to the papillary
or reticular dermis. This cannot be considered as just a poten-
tial complication. On the contrary, it should be considered as
an almost certain side effect of peels to these depths. Herpes
prevention is therefore obligatory. Only Touch is a deep peel
(b)
(a)
Figure 37.47  (a) Acneiform dermatitis on the neck, 7 days after a full-face phenol peel: a sign of skin infection. (b) After 13 days, the
acneiform.

358      Textbook of Chemical Peels
that reaches the reticular dermis, but because its use is limited
to areas of 1 cm in diameter at most, the immune defenses are
not damaged enough to trigger herpes, and there have been
no cases of herpes described after this peel. No prevention is
necessary.
Specific Herpes Symptoms after a Peel
Diagnosing a herpes outbreak is relatively complex in the days
following a peel, because the superficial layers of the epidermis
have been removed and this is where the blisters that allow easy
diagnosis form. Sometimes herpes will manifest only as pain-
ful erythema (Figure  37.48b), but sometimes also in a clearly
necrotic form. The herpes outbreak may be delayed and occur
after the 8th day. In general, the sudden onset of pain accompa-
nied by erythema between the 4th and 7th days is a sure sign
of herpes. The herpes can spread over the whole face within a
few hours, but fortunately does not usually leave any scars.109
It appears that there have been no cases of herpes spreading
to the eyes after a medium or deep facial peel.106 Severe local
outbreaks can, however, leave local hyper/hypopigmentation.
Differential Diagnosis: Herpes/Bacterial Infection
An infection can be assumed to be herpes if the patient has a
personal history of herpes. If pain is felt on the upper lip first,
this also suggests herpes, while pain felt on the cheek would
suggest a bacterial infection, especially if there are scratch
lesions and pus. Given that the epidermis has been exfoliated
by the medium or deep peel, the doctor should not expect to see
herpes blisters.
Pain is an important clinical sign. Herpes is painful even
before it is visible, whereas a bacterial infection is usually pain-
less or only becomes painful after it has developed clinically for
a certain amount of time.
Differential Diagnosis: Herpes/Overpeeling
In addition to the signs and symptoms already described, over-
peeling does not usually cause much pain at first, whereas her-
pes does.
Prevention of Herpes Outbreaks
Herpes prevention is sometimes advisable with a peel to the
Grenz zone, and is essential with peels to the papillary or retic-
ular dermis (except for Only Touch; see previous discussion).
Questioning the Patient and Clinical Examination  In the major-
ity of cases, patients forget that they once had a “cold sore”
when they had the “flu” several years ago. Therefore, the doc-
tor should look very carefully for any dyschromia in places
where herpes is usually located, and should not forget that
herpes may develop in other areas apart from the upper lip,
as can be seen in Figure 37.49, which shows herpes located in
the ear.
Preventive Treatment
•
Aciclovir: two tablets two times a day, 3 days before and
5 days after a medium or deep peel, or
•
Valacyclovir: 500 mg two times a day, 2 days before and
5 days after a medium or deep peel.
Treating Postpeel Herpes Outbreaks
Oral Antiviral Treatment  This comprises aciclovir by mouth
from 400 mg four times per day to 800 mg five times per day,
or valaciclovir by mouth: from 500 mg three times per day to
1 g three times per day. The higher doses are for treatment of
herpes outbreaks that have occurred in spite of proper preven-
tive treatment.
(a)
(b)
Figure 37.48  (a) Secondary herpes infection 5 days after a TCA peel to the papillary dermis. No herpes prevention treatment was used.
(b) Close-up of the upper lip: only painful erythema can be seen; treatment with valaciclovir brings rapid remission without hyperpigmenta-
tion or scarring.

Complications of chemical peels      359
Topical Treatment  Topical aciclovir is not well tolerated by
patients after a deep peel because of the burning sensation
it triggers.109 If pain is very local, EMLA cream can be used
­cautiously, as it is absorbed more readily through skin that has
no stratum corneum and is damaged by herpes. Local cortico-
steroids should not be used.
Treating Pain and/or Pruritus  Nerve blocks can be given in
cases of very painful outbreaks. A mixture of lidocaine with
adrenaline (epinephrine) and ropivacaine or bupivacaine110 can
be used. In some cases, the doctor will have to prescribe opioids
to relieve severe pain. However, treatment with opioids might
well eliminate the pain but will not affect the itching. It could
even aggravate the pruritus. The itching sometimes resists
hydroxyzine and diphenhydramine. Asken109 reported that he
once had to inject propanolol intravenously to relieve unbear-
able pruritus.
Benzodiazepines111 and strong analgesics112 sedate
patients and prevent scratching, secondary infections, pigmen-
tation problems, and permanent scars. Daily doctor–patient
contact is essential to reassure the patient that the herpes
lesions are healing properly.
Special Case of Herpes under Post-Phenol Occlusive Mask  It is dif-
ficult to diagnose and impossible to monitor herpes outbreaks,
large or small, beneath an opaque occlusive mask of ­bismuth
subgallate or thymol iodide. If there is any hint of herpes, any
acute pain between the 4th and 7th day after the ­phenol, the
powder mask113 should be removed immediately so the doctor
can examine the skin thoroughly. If the doctor’s suspicions are
confirmed, the herpes should be treated as described earlier.
Once the diagnosis has been made, the powder mask should
not be replaced, and the “moist” technique should be used
instead, with regular application of an antibiotic cream (e.g.,
bacitracin) to avoid secondary bacterial infection.
PRURITUS
All peels destroy at least part of the epidermis and stimulate
keratinocyte growth. The rapid dehydration of the noncorni-
fied keratinocytes can cause pruritus, which, however, is easily
controlled.
Superficial Peels
Intraepidermal peels or peels to the basal layer rarely cause
pruritus, except in overpeeled areas, where it may be tempo-
rary. Peels to the Grenz zone do not cause much pruritus. There
have been no reports of severe pruritus with Easy TCA, except
for two cases of allergy to the postpeel cream.114
Dermal Peels
Pruritus is a logical result of a dermal peel. It sometimes starts
very quickly, toward the 3rd day, or later, between the 8th and
30th days. It gradually becomes less severe and eventually dis-
appears on its own.
Medication is sometimes necessary for patients who tend
to scratch and are at risk of causing lesions, secondary infec-
tions, or scars. Sublingual lorazepam (2.5 mg) or promethazine
(25 mg/tablet, 2–6 tablets a day) usually stops postpeel pruritus.
A calm or sleepy patient tends not to scratch. Cool ­compresses
can also be applied. Cool compresses help the patient cope with
the pruritus, but frozen compresses are not advised immedi-
ately after a dermal peel.
Following a phenol peel, pruritus usually starts gradually
underneath the bismuth subgallate powder mask. The patient
must be told not to scratch, because if the powder mask is
pulled off accidentally when scratching, it may create bleeding
lesions that could become infected (Figure 37.50). Fortunately,
these lesions heal rapidly and only leave a few areas of dys-
chromia. Instead of scratching, the patient should gently tap
any area that is itching.
FACIAL EDEMA
All peels cause edema in the treated area. In fact, all peels trig-
ger an inflammatory reaction whose cardinal signs are “rubor,
dolor, tumor, calor.”115 The redness (rubor) and heat (calor) come
from vasodilation that enhances the passage of liquids through
the vascular endothelium and causes swelling (tumor), whose
rapid onset can be painful (dolor). The pain can be superficial
and more than a feeling of tightness when the inflammation is
limited. The inflammation is also due to the presence of pro-
inflammatory components in the dermis, which, together with
the increased oxygen supply (because of the vasodilation), pro-
motes the formation of free radicals. The free radicals damage
the neighboring structures and maintain the inflammation.
The result is a “vicious cycle” in which vasodilation promotes
inflammation that causes vasodilation.
From a physiological point of view, the movement of flu-
ids follows Starling’s hypothesis (1896):116

movement of fluid = K [(CP + IO) – (IP + PO)]
where CP and IP are the capillary and interstitial hydrostatic
pressure, IO and PO are the interstitial and plasma osmotic
pressures, and K is the filtration constant for the capillary mem-
brane. If the resultant is positive, there is plasma filtration into
the interstitial space. If the resultant is negative, there is absorp-
tion into the capillary lumen.
Figure 37.49  Unusual location of herpes blisters in the helix
above the tragus. Dermatitis has been cured with oral antibiotics.

360      Textbook of Chemical Peels
The edema creates an additional barrier to capillary
absorption by increasing the physical distance between the
capillary wall and the molecules to be absorbed.116 If the edema
resolves rapidly by itself, it does not need treatment.
The rapid onset of edema dilutes the acids that arrive in
the immediate surroundings of the blood vessels and prevents
protein coagulation in the vessel walls: blood continues to
circulate. When there is too much acid, extravascular plasma
filtration can no longer make up for the fall in pH, and the ves-
sel walls coagulate. Blood no longer circulates, and the skin
changes color from pink-white to pure white or even gray.
Severity of Edema Depending on Peel Type
Peels to the Epidermis or Basal Layer
Edema comes from dermal inflammation, and peels that do
not cause inflammation in the papillary dermis do not cause
much edema. If the patient has an allergic reaction to one of the
components used (e.g., resorcinol), then severe edema can set
in rapidly, however. Any severe edema after a peel that does
not go beyond the basal layer is most likely associated with an
allergy or infection.
Peel to the Grenz Zone
Mild and short-lived edema (48 hours) might develop.117 It does
not require treatment. Edema that lasts any longer could be an
allergy and, if so, should be treated accordingly.
Peels to the Papillary or Reticular Dermis
A peel to the papillary dermis always causes edema, whose
severity depends on the inflammatory reaction following the
peel (Figures 37.51–37.53). An inflammatory reaction is desir-
able insofar as it triggers the skin regeneration process; it is
therefore responsible for the rejuvenating effect of a peel. But, at
the same time, it generates free radicals that have well-known
negative effects. Inflammation therefore has its downside and
must be controlled by antioxidants to limit the negative side
and make the most of the restructuring effect. This is why Easy
TCA, Unideep, and Easy Phytic are rich in antioxidants, both
in the peel solution and in the cream “mask” that the doctor
applies immediately after the peel. These antioxidants reduce
postpeel inflammation, allowing patients to resume their
social activities more quickly and allowing more frequent rep-
etition of the peels. In general, the deeper the peel, the more
severe the edema, as the edema translates the severity of the
dermal inflammation into visible signs. It is therefore logical
that edema is more severe after a phenol peel. The extent of the
“lifting effect” of a peel depends on the depth of the peel and
the severity of the edema. It can therefore be concluded that the
overall lifting effect of a peel will be proportional to the edema
it triggers. Edema is sometimes so severe as to cause the lips to
protrude118 or to prevent patients from opening their eyes.
Deep peels therefore give rise to dramatic edema that can
sometimes be very worrying for patients and their immediate
friends and family. A case has been reported of a patient whose
family members rushed her to the nearest hospital; they were
worried about what appeared to be severe burns.
It is essential to warn patients of the severity of the edema
and to show them photographs of the postpeel period so that
they do not worry. If a detailed explanation is not given before-
hand, anything the doctor might say after treatment will ring
(b)
(a)
Figure 37.50  (a) Scratch lesion after a phenol peel, treated with bismuth subgallate. Note the intense and uneven erythema 10 days
after the peel. (b) The scratch lesion has completely healed. This photograph was taken about 5 years after (a), during the course of other
treatment.

Complications of chemical peels      361
(b)
(a)
Figure 37.52  (a) Before a TCA peel to the papillary dermis. (b) Facial edema 24 hours after TCA to the papillary dermis (Unideep).
(b)
(a)
Figure 37.51  (a) Edema beneath the occlusive mask, 24 hours after a phenol peel. (b) Facial edema after the occlusive mask has been
removed, 24 hours after the peel. A bismuth subgallate powder mask has just been applied.

362      Textbook of Chemical Peels
hollow to the patient and his or her friends and family. It is
extremely important for the doctor to have regular contact with
the patient during the first week after the peel, as the doctor
can check on progress every day and reassure the patient that
everything is normal.
Link between Pain and Edema
Fortunately for the patient, there is no linear relation between
the pain felt and the severity of the edema. It is not painful even
when it is so severe that patients cannot open their eyes for
anything from a few hours to several days, depending on the
formula used. If after the 3rd day the edema is painful, there
might be a secondary infection.
Edema and Local Phenol Peel
A local phenol peel on the eyelids or lips (Lip & Eyelid) also
gives rise to severe edema (Figure  37.54) that can make it
difficult for patients to eat or open their eyes, which can make
some patients extremely anxious. This edema reaches its peak,
locally, during the first 2 days and then subsides according to
the laws of gravity. During the 3rd and 4th days, edema of the
eyelids migrates downward to the cheeks and then the jaw,
reaches the neck on the 5th day, and disappears on the 6th or
7th day. The edema that follows a localized phenol peel on the
lips subsides more quickly, as it has less distance to cover before
it reaches the neck.
Prevention of Edema
Peels to the papillary dermis and especially to the reticular
dermis trigger the most dramatic edema, and it is only in these
cases that prevention should be considered. The severity of
the edema is hard to predict; some patients have (­relatively)
little swelling, whereas others have severe edema even before
the whole face has been treated. Preventive, intravenous
(b)
(a)
Figure 37.53  (a) Before the peel. (b) Facial edema the day after a TCA peel to the papillary dermis (Unideep): note that the edema on the
first day eliminates not only the cheek wrinkles but also the facial sagging. The erythema is reduced by antioxidants in the postpeel cream.
(b)
(a)
Figure 37.54  (a) Appearance of the upper lip before a phenol peel (Lip & Eyelid Formula). (b) Appearance of the upper lip 24 hours after
Lip & Eyelid.

Complications of chemical peels      363
­injections of corticosteroids before the peel do not appear to
make much difference, and the edema develops in spite of the
corticosteroids.
With phenol peels, it is often possible to limit edema in
the upper eyelids by not treating the skin of the upper eyelid
tarsus (Figure 37.55). The eyelid edema is then less uncomfort-
able for the patient.
When the impermeable dressing (occlusive phenol) is
being applied, it should not be placed too close to the eyes, to
avoid excessive swelling on the part of the eyelids not covered
by the occlusive dressing.
Treating Edema
Small paper or textile bags containing China tea, after they
have been boiled and cooled in the refrigerator, make excellent,
refreshing compresses that can be used to alleviate the discom-
fort of eyelid edema. The patient should sleep in a half-sitting
position to help the edema go down. The doctor should wait for
some months before judging the permanent effect of the peel.
As the swelling goes down, wrinkles that have not responded
to the medium or deep peel reappear on the patient’s skin.
It is not necessary to prescribe diuretics in the large
majority of cases. Edema associated with an infection or an
allergy should be treated accordingly.
Steroids and nonsteroidal anti-inflammatories should be
avoided so as not to interfere with collagen generation. Oral
Varidase119 can be used to help the swelling subside.
MILIA
These small epidermal inclusion cysts120 are a relatively com-
mon and fortunately benign complication of medium or deep
peels, and occur mainly when the peels have been followed by
greasy occlusion or occlusive makeup. They can vary in num-
ber from a single cyst to several hundred, and usually appear
in the midface region or on the cheeks. A latency period of sev-
eral weeks (3–6) is necessary before they become visible, and
it takes 6–12 weeks for them to disappear, unless patients run
out of patience and remove them themselves or ask the doctor
to do it.
Prevention of Milia
Topical Tretinoin
Applying topical tretinoin (all-trans-retinoic acid) before a
peel can often reduce the incidence of milia. However, the
undesirable effects of retinoic acid in combination with a deep
or medium peel must be taken into account. Retinoic acid
increases the depth of penetration of caustic agents, could
increase the risk of hyperpigmentation68 and, if it is applied
too soon after a medium or deep peel, slows down the rate of
reepithelialization.
Dry Technique for Phenol
During the phase of skin regeneration that follows a phenol peel,
the “dry” technique121 should be used instead of the “moist”
technique that most often causes milia to form. Inclusion cysts
rarely occur when the “dry” technique is used, and if they
do, they are small, few in number, and leave no marks after
excision.
Treating Milia
Patients should not try to remove these small, white, subcuta-
neous cysts themselves. If they are handled unnecessarily or
too roughly, sometimes with the help of unorthodox instru-
ments, secondary infections and/or scars can follow, and the
milia can remain deeply embedded in the skin. At the most,
patients can use a Buf-Puf (3M) sponge to gently scrub the skin
if it is not too sensitive.
One of the easiest ways to treat milia is simply to wait.
Milia should be given time to clear up by themselves: a period
of 1 month is left for them to clear, by which time reepitheli-
alization is complete. The doctor should carefully make an
­incision in the top of each cyst with the tip of a No. 11 scal-
pel or an 18G needle, which will make it easier to extract them
with a blackhead remover without leaving any marks, as the
cut is strictly intraepidermal. This treatment is carried out with
­sterile equipment after disinfection, and there is no need for
local anesthetic.
ACNE
Acne can be either treated or triggered by a peel. An intraepi-
dermal peel (Easy Phytic) or a peel to the basal layer (Easy TCA)
is usually a good treatment for comedonal, papular, or even
papulopustular acne. Intraepidermal peels or peels to the basal
layer do not usually trigger postpeel acne, unlike peels to the
papillary dermis, which can promote secondary infections.
Active acne must be treated in the weeks before a peel to
the papillary or reticular dermis, and the medium or deep peel
can only be started once the infection has completely cleared.
The increased epidermal permeability resulting from prescrip-
tion treatments must be taken into account.
Doing a papillary or reticular dermal peel during the
active phase of pustular acne would trigger a potentially seri-
ous infection of the whole treated area that could even develop
Figure 37.55  Frosting of the skin after application of Lip & Eyelid
Formula: note that the skin of the upper eyelid tarsus has not been
treated, to limit the postpeel edema.

364      Textbook of Chemical Peels
into toxic shock. A fortiori, peels should not be performed on
patients suffering from active acne conglobata, necrotica, and
so forth.
Some comedones may occur in certain patients during
the postpeel period; they should be extracted with a blackhead
remover.
It is common for acneiform dermatitis to develop under
greasy dressings (see also the section earlier in this chapter on
microbial infections) after deep peels treated with the “moist”
technique. Vaseline creates an impermeable layer that acts as
total occlusion. It is known that bacterial proliferation is much
more rapid under occlusion than in the open air. Antibiotics
and standard local treatments are used to treat postpeel acne.
PAIN
The pain threshold is virtually the same for all human beings,
who perceive the stimulation of their nociceptors from the
same intensity threshold. Pain tolerance, however, varies con-
siderably from one patient to another. It is very important to
consider patient psychology, especially during the first peel
session. Patients have absolutely no idea what they are about to
go through, and words like chemical or burn evoke images that
contribute to the general anxiety generated by the first sensa-
tion of pain. Peels that do not go beyond the Grenz zone have to
be repeated several times to be effective. The first session is the
most painful, as the patient feels the pain “blindly,” not knowing
what is going to happen next, and becomes increasingly anxious,
which amplifies the sensation of pain. Patients find the follow-
ing sessions less painful, as they can anticipate when the pain
will stop. In general, pain tolerance seems to increase with age.
Contrary to rumor, men have a slightly higher pain sensitivity
threshold than women, but women, who are more used to pain,
tolerate it (much) better. It is personality more than race or gen-
der that influences how a person experiences pain, and it is often
difficult to draw the line between pain and suffering, sensation
and emotion, and pain experienced and pain felt, as regardless
of a person’s pain threshold, in the end the pain always feels real.
Pain during Application of the Peel
The pain caused by a peel is largely proportional to its depth.
The type of pain, its intensity, and its duration vary depend-
ing on the peel used. It is recommended to give patients details
about the pain they will feel, how intense it will be, how it will
develop, and how long it will last. It is essential to tell them
about any change in technique, as patients may become anxious
if the pain they feel is different from what has been described.
AHAs
Partially buffered glycolic acid at 50% or 70% is not painful.
Unbuffered 70% glycolic acid (with pH <1) causes a burning
sensation that is as bearable as it is short-lived. Neutralization
with a solution saturated in sodium bicarbonate immediately
stops any burning sensation. Other AHAs are less aggressive
on the skin and less painful. The pain decreases as the molecu-
lar weight of the molecules increases, as larger molecules have
more difficulty penetrating the skin. Lactic acid is sometimes
used to test skin sensitivity (the stinging test): applying a 10%
solution triggers a burning sensation in patients with sensitive
skin. Easy Phytic Solution (glycolic, lactic, mandelic, and phytic
acids in a self-neutralizing solution) produces a specific type
of pain that starts with rapid burning from the glycolic acid,
quickly followed by a relatively painless tingling sensation that
soon decreases in intensity. These sensations arise from the
successive and gradual penetration of the different acids and
their natural neutralization by the skin.
TCA
Peels to the Papillary or Reticular Dermis:  The pain caused by
TCA is directly proportional to the concentration of the acid
in the solution applied: a solution at 20% m/m burns less than
a solution at 30% m/m. Pain is one of the signs that alerts the
doctor immediately to any error in the formulation used. If the
patient complains of a very intense burning sensation when
a solution that is not supposed to be too aggressive has been
applied, it is important to stop the application and check whether
the solution has been properly prepared. A peel to the papillary
dermis is always painful, but the intensity of the pain does not
always warrant local anesthesia; it is often enough to talk to the
patient, explain the pain and the different phases of the treat-
ment, and anticipate when the pain will stop. Patients are grate-
ful, however, when the doctor administers nerve blocks before
applying the acid. It is not necessary to block the whole face,
and supraorbital, suborbital, and mental blocks significantly
reduce the intensity of the pain. With these nerve blocks, appli-
cation to the forehead and midface region is completely pain-
less. To avoid overreactions, more squeamish patients could be
given mild premedication or sometimes, although rare, deep
sedation before a peel to the papillary dermis. When TCA is
applied to the reticular dermis, premedication, deep sedation,
and/or nerve blocks will be necessary, as peels of this depth are
very painful. The anti-prostaglandin action of aspirin reduces
the burning sensation and provides relief to many patients:
500–1000 mg of aspirin taken 45–60 minutes before the peel can
therefore be recommended if the peel is to reach the papillary
dermis. There is a greater risk of bruising, however.
The Unideep peel (TCA to the papillary dermis combined
with an antioxidant, stimulating, and analgesic postpeel mask)
has the advantage in that it can be applied region by region and
the patient benefits from the almost immediate analgesic effect
of the postpeel cream mask that is applied as soon as frosting
is achieved. The forehead is treated first until even pink-white
frosting appears, and the postpeel cream is applied on this area
before starting treatment on the next area. Patients soon expe-
rience the rapid relief brought by the postpeel cream, which
makes them less anxious about the rest of the treatment.
Using cold packs (ColdHot Pack by 3M) before applying
the Unideep solution can be effective: cooling the skin before
applying the solution alleviates most of the pain. It seems that
most of the pain comes from the sudden warming of the pap-
illary dermis after vasodilation; the heat-sensitive nociceptors
in the papillary dermis cannot react as strongly when they are
cooled beforehand with cold packs. Using cold packs is there-
fore effective both before applying the peel solution and imme-
diately afterward—the plastic of the cold packs can come into
direct contact with the acid in Unideep (Figure  37.56). Some
patients, however, find the cold almost as unpleasant as the bite
of the acids, and prefer simply to have their skin fanned with a
handheld or electric fan. Squeamish patients will appreciate a
frontal nerve block. The Unideep solution is applied to the fore-
head first and taken beyond the anesthetized region toward the
temples. The postpeel cream immediately stops the sensation
of pain, and the rest of the face can be treated easily, without
nerve blocks, as patients can accept pain that they know to
be short-lived and bearable, having felt it on the temples and
expecting it to be “blocked” by the postpeel cream.

Complications of chemical peels      365
Only Touch is an adjuvanted and saponified solution
with a concentration of 45% m/m of TCA. Localized application
to small, benign lesions with a maximum diameter of 1 cm trig-
gers intense burning that is not too unpleasant, as it is limited
in extent. Only Touch does not require any type of anesthesia.
When treating a large number of lesions, as is often the case
with lentigines on the hands or décolletage, the patient may
appreciate the use of cold packs to reduce the burning sensa-
tion (Figure 37.57). The cold pack can be used in two ways: the
doctor either waits for the acid to dry before applying the cold
pack on the skin with a sheet of paper in between or applies the
plastic of the cold pack directly on the acid as it is taking effect.
The acids used do not damage the plastic of the cold pack, and
this type of immediate and direct application seems to be the
most effective at reducing the pain.
Peels to the Basal Layer or Grenz Zone  Easy TCA, an adjuvanted
and saponified solution with 15% m/m TCA,122 produces a sen-
sation of heat or mild burning that the vast majority of patients
find easy to bear. More squeamish patients will complain of
feeling some pain, but it is short-lived, as the postpeel cream
alleviates it immediately.123 After the postpeel cream has been
applied, there is only a feeling of tightness.
Phenol
Phenol is used to regenerate the skin down to the reticular
dermis. It has useful neurolytic and anesthetic properties. The
pain is therefore short-lived (around 15 seconds), as the phenol
produces local numbness that lasts from 20–30 minutes. After
this time, the inflammatory phenomena in the dermis become
powerful enough to trigger a painful and intense sensation of
heat that will slowly subside over the next few hours and days.
Recently, some phenol formulas have been presented
as allowing a full-face peel without any anesthetic. A phenol
peel that can be applied to the whole face without any type of
anesthetic is a more superficial phenol peel that does not induce
regeneration of the reticular dermis of the same quality as the
“classic” phenol peels. Less pain goes hand in hand with inad-
equate results: the results of this type of phenol peel are the
same as for a TCA peel to the papillary dermis and may not
have much effect on wrinkles. The pain caused by these peels
is also the same as for a TCA peel to the papillary dermis. It is
pointless to put a patient through the risks of phenol toxicity
only to get the results that a simple, nontoxic molecule (TCA)
can achieve. An effective, full-face phenol peel should therefore
be used with an anesthetic (see Chapter 33).
A localized Litton or Baker–Gordon peel can be per-
formed with short-acting nerve blocks with 2% lidocaine
without adrenaline (epinephrine). The pain is also short-lived.
Phenol provides anesthesia that extends about 1 cm beyond the
frosting, and the phenol can be applied slowly, step by step.
Chemical blepharoplasty and cheiloplasty124 are ideally
performed with Lip & Eyelid Formula: its action is more grad-
ual than that of Baker–Gordon or Litton phenol, and it can be
applied locally without any anesthetic since the pain only lasts
12–15 seconds.
Phenol is neurolytic; it makes the skin less sensitive for
several days, and it is possible to touch up certain areas with-
out causing any real pain after the nerve block anesthesia has
worn off, even the day after the peel. Even if deep inflammatory
phenomena make the dermis painful, the epidermis remains
insensitive.
Figure 37.56  Cryoanesthesia with a cold pack during combined
chemical blepharoplasty (Lip & Eyelid) and TCA to the papillary
dermis (Unideep).
Figure 37.57  Use of a cold pack during treatment of lentigines on
the hands with Only Touch.

366      Textbook of Chemical Peels
Postpeel Pain
AHAs
Neutralization, which relieves the pain, can sometimes be
unpleasant, as the process of AHA neutralization is slightly
exothermic. The pain subsides very quickly after any intraepi-
dermal peel.
Easy TCA and Unideep
The Easy TCA (to the basal layer or Grenz zone) and Unideep
(to the papillary dermis) postpeel mask cream has the major
advantage of relieving the burning sensation caused by the
acids almost immediately.
Using cold packs as soon as the peel is over usually pro-
vides relief to the patient.
No specific treatment is necessary for the pain that comes
immediately after peels to the papillary dermis.
Only Touch
There is almost no residual pain after Only Touch.
Peel to the Reticular Dermis
The fact that patients look as if they have third-degree burns
after a peel to the reticular dermis has no relation to the pain
they actually feel (Figure 37.58).
After a phenol peel, the type of pain experienced var-
ies enormously, and descriptions given by different patients
of the intensity of the pain range from “completely painless”
to “extremely painful.” Opioids are sometimes necessary to
relieve severe pain.
A combination of acetaminophen plus codeine is espe-
cially well suited to postpeel pain but should not be used in
the hours following a phenol peel, as acetaminophen (a phenol
derivative) goes through the same detoxification pathways
as phenol, which could create metabolic competition and the
risks of toxicity associated with phenol might be increased.
Preventive administration of benzodiazepines (lorazepam
2.5 mg before the peel and on the night of the peel before going
to bed) relieves the anxiety caused by these unpleasant sensa-
tions and reduces the need for analgesics after the peel. In case
of very severe, localized pain (extremely rare), a nerve block
could be used.
Often, the pain described by the patient is an unpleasant
sensation of heat, due to extensive vasodilation that immedi-
ately follows a deep peel. A cold pack can help the patient get
through this phase.
The pain that occurs after a phenol peel can be summa-
rized as follows:
•
Application of phenol: followed by 15 seconds of pain.
•
Phase of anesthesia: 30–60 minutes.
•
Phase of burning and painful edema: sets in within 1–2
hours and lasts until the following morning.
•
Phase of simple tightening of the skin: up to the 3rd day.
•
Pulsing type pain: usually during the 3rd night, with an
average duration of 8 hours.
•
Any feeling of pain then stops definitively, and pruritus
sets in from the 4th or 5th day.
SUN SENSITIVITY
All peels, even if they do not cause any visible flaking, damage
the skin’s protective stratum corneum and make it more sen-
sitive to all types of aggression. Light consists of high-energy
particles called photons. Photons are absorbed by the ozone
layer and oxygen in the atmosphere, and only 7.1% of solar
energy reaches the Earth. Photons move in waves and have a
characteristic wavelength and frequency. They are absorbed
in the skin, where they cease to exist and are converted into
energy. UV rays have wavelengths between 100 and 400 nm,
but only UVA (320–400 nm) and UVB (290–320 nm) reach the
Earth, as the ozone layer blocks UVC.125 High frequencies have
the most energy. (Gamma rays have the most energy, and UV
rays have more energy than infrared.)
Different variables affect the intensity of solar radiation.
As the emission of solar radiation is considered constant, the
summer sun is “stronger” than the winter sun, the sun at the
equator stronger than the sun in Lapland, and the midday sun
burns more than the afternoon sun. Fog does not slow down
UV penetration, but urban pollution is, on the contrary, a pow-
erful sunblock because of the presence of aromatic hydrocar-
bons, which make excellent UV blocks. Altitude in itself has
less influence than the angle of incidence, but snow, on the other
hand, reflects 85% of UV rays, whereas dry sand reflects only
17%, water 5%, and grass 2%. Therefore, places lying between
snow-covered mountains on a very sunny day are particularly
dangerous.
After penetrating the skin, photons are absorbed by
specific molecules called chromophores. Each chromophore
absorbs a set wavelength. Photons that penetrate the skin are
converted into energy, and this produces biochemical changes
that make certain molecules unstable by putting them in a
higher-energy state. Some molecules can convert this energy
into heat and/or vibrations and thus regain their original
stable state (e.g., eumelanins behave in this way). The energy
absorbed can also break certain intramolecular bonds and con-
vert some molecules into free radicals. These free radicals are
very reactive and will bind rapidly with other chemical species.
Figure 37.58  After a phenol peel, patients look as if they have
third-degree burns but in fact feel no pain at all.

Complications of chemical peels      367
Free radicals can also attack the DNA molecule and
block its replication locally. They can sometimes break the
DNA molecule during the replication phase of the cell cycle,
before the mitosis phase, or if photosensitizing molecules are
used. Fortunately, human cells contain mechanisms for the
repair of damaged DNA, involving DNA polymerase and other
enzymes.
The polyunsaturated fatty acids that make up cell mem-
branes are very sensitive to free-radical attacks. The CH2 group
that is located between the double bonds of arachidonic acid
degrades as a result of free-radical attacks; it forms unstable
peroxides, and at the end of these chain reactions a malonedi-
aldehyde molecule is released at the same time as two new free
radicals, and these spread the reactions to the rest of the mem-
branes. Once the free-radical reaction has started, the damage
spreads quickly. Some amino acids, either free or as components
of proteins, can absorb UV rays, leading to photoionization
and releasing electrons that initiate reactions that damage pro-
teins. Moreover, in the presence of oxygen, oxygen free-radicals
are formed that then react with organic molecules to produce
hydroperoxides. These can then damage proteins both by break-
ing polypeptide chains and by forming bridges between them.
In short, sunlight damages the genetic code, cell mem-
branes, intracellular organelles, proteins, enzymes, and more.
Moreover, only 25% of the erythema dose is needed to cause
potential damage to the genetic code of human cells.
We have numerous defense mechanisms to protect us,
and complex physiological reactions can repair most of the
damage caused by photons. Some of the light from the sun is
reflected off the fatty layer covering the corneocytes. The out-
ermost layers of the stratum corneum also reflect light, and the
photons that manage to penetrate this layer are diffused as they
reflect off the different layers of cells.
The UV photons that have not been reflected or absorbed
reach the basal layer of the epidermis, the papillary dermis, and
the reticular dermis. UVA rays that are emitted perpendicular
to the skin penetrate deeply: 66% get through the stratum cor-
neum and 44% reach the basal layer. They have relatively little
effect on the epidermis, but do severe damage to the dermis.
Some 17% of UVB rays get through the stratum corneum, and
3% reach the basal layer. They cause more damage to the epi-
dermis than to the dermis. The thickness of the stratum cor-
neum is therefore an important part of the skin’s defenses, and
treatments that damage it (dermabrasion, laser, AHA creams,
peels, etc.) allow photons in and promote the free-radical
­damage described earlier.
The angle of incidence of solar rays is important: at ver-
tical incidence, the photons only have to cover 15 µm through
the corneocytes, while, at oblique incidence, they have to
cover up to 35 µm to reach keratinocytes. The morning or late
afternoon sun is therefore less dangerous than the midday
sun.
Skin color is in itself a defense mechanism: white skin
lets in up to 64% of rays that touch it, and black skin is perme-
able to only 18% of these rays. White skin suffers from photoag-
ing much more quickly than black skin. Yellow skin has fewer
pigments than black skin, but the stratum corneum is thicker
than that of Caucasian skin and is better at reflecting and dif-
fusing photons.
Beta-carotene, superoxide dismutase (SOD), and catalase
(CAT) are vital free-radical defenses. Epidermal beta-carotene
diffuses from the dermis and can scavenge free radicals. SOD
and CAT block the oxidative action of UV photons. SOD blocks
the first stage of oxidation, the formation of the superoxide
anion. The level of SOD in the body has been directly correlated
with life expectancy. Organisms with the most SOD live the
longest. Some cosmetic preparations use SOD. This unstable
molecule has to be protected, ideally in liposomes, to prevent it
from being oxidized.
These facts give us a better appreciation of the need for
effective sun protection. Just one peel, of whatever kind, makes
the skin more sensitive to the sun. Patients soon feel the dif-
ference just hours after treatment and complain that they can
no longer expose their skin to direct sunlight because of the
burning sensation this causes. The deeper the peel, the more
sensitive the skin is to the sun. The thinned or absent stratum
corneum cannot provide protection against the sun’s rays until
the epidermis has completely recovered.
After a deep peel, the skin is like that of a newborn baby
and remains sensitive to the sun for a long time. It is therefore
recommended to keep using total sunblock126 and avoid the sun
for a duration that is directly proportional to the depth of the
peel.
DEMARCATION LINE
A deep peel restructures the skin permanently and changes the
quality and structure of the skin irreversibly. Treated skin is
cleared of actinic lesions, and there is a visible line between the
treated and untreated skin. This is called a “demarcation line”
and can result from a difference in the quality or color of the
skin (Figure 37.59). A difference in color is more obvious than a
difference in the texture of the skin.
It is easy to predict the risk of a visible demarcation line
(Figure 37.62). Not counting the hypopigmenting (with phenol)
or hyperpigmenting (with TCA) properties of different peeling
agents, the parameters that should be taken into account are the
depth of the peel and the patient’s skin type.
Figure 37.59  Neck demarcation line after a full-face phenol peel.

368      Textbook of Chemical Peels
Depth of Peel
Intraepidermal peels or peels to the basal layer of the epidermis
do not create a demarcation line. TCA peels to the papillary
dermis can change the texture and color of the skin, but there
is often no visible demarcation line after TCA to the papillary
dermis. TCA is not toxic to melanocytes. It can, however, elimi-
nate the majority of freckles if it reaches the papillary dermis,
and there will be a visible demarcation line between the skin
with and the skin without freckles. A phenol peel is deep127 and
toxic to melanocytes, and it is with this type of peel that there is
a greater risk of a demarcation line.
Skin Type
High skin phototypes (IV–VI), dark or Asian skin, and tanned
or very sun-damaged skin are the most at risk of a demarca-
tion line after a medium or deep peel. Skin phototypes I–III
very rarely suffer from permanent postpeel pigmentation
problems; the only possible visible difference would be in the
texture of the skin. Figure 37.60 shows the absence of a color
demarcation line in a patient with a light skin type who has
had a combination of a localized deep phenol peel on the eye-
lids (Lip & Eyelid) and a TCA peel to the papillary dermis
on the rest of the face (Unideep). The results shown are after
1 year. The phenol has clearly made the skin firm again, and
the medium-depth TCA has significantly improved the sun
damage. Nevertheless, there is still a slight visible difference
in the structure of the skin between the areas treated with
phenol and those treated with TCA to the papillary dermis.
There is a particular risk with very sun-damaged skin, as the
medium or deep peel restructures the skin to such an extent
that it leaves a very visible difference in the quality of the
treated and untreated areas. Loss of tanning is proportional
to the depth of the peel: intraepidermal peels lighten a tan
and deeper peels get rid of it altogether. A deep and local-
ized treatment on tanned skin will always remove the color
in the treated area that will appear all the lighter against the
surrounding, tanned skin. Tanned, sun-damaged skin with
a high phototype and dark or Asian skin should always be
treated in such a way that the inevitable demarcation lines
will not be visible.
This is where the finer details of peel application count,
as certain areas are more likely to develop demarcation lines
than others.
High-Risk Areas
The Forehead
Prevention consists of applying the peel in the hair, about 1 cm
beyond the hairline. Neither phenol nor TCA are toxic to the
hair bulb. There is no danger of localized alopecia.
The eyebrows should be treated against the lie of the hair
so that the peel comes into contact with the skin underneath
the eyebrows.
White Lip–Red Lip, Nostrils
Prevention consists of taking the peel slightly over onto the
oral mucous membrane and treating the skin on the edges
of the nostrils, up to the junction of the mucous membrane.
Contact between phenol and the first millimeter of the lip
mucous membrane does not pose any problem, and allows the
doctor to treat fine lines at the same time as avoiding a visible
and unsightly demarcation line around the lips. Aged lips might
take advantage of carefully applied phenol on the red lip.
The Ear
Prevention consists in feathering the tragus and the earlobe.
The Neck
Prevention consists in clearly setting the lower limit of the
peel before treatment, with the patient in the sitting position.
If an occlusive phenol peel is used, the occlusive dressing
should not be put under the lower jaw. The absence of occlu-
sion under the jaw, between the face and the neck, reduces
local maceration and therefore the depth reached; this cre-
ates a transition zone in the area of shadow beneath the jaw
(Figure 37.61).
DILATED PORES
Benatar128 describes this complication when doing deep-peel
treatments on patients with thick, oily skin and dilated pores.
The results of deep peels—and especially medium peels—are
(a)
(b)
Figure 37.60  (a) Eyelid aging before treatment. (b) Results 1 year after application of Lip & Eyelid Formula (upper and lower eyelids) and
Unideep to the rest of the face to even out the results.

Complications of chemical peels      369
mediocre compared with the dramatic results seen when treat-
ing drier and thinner skins. Thick, oily skin with dilated pores
benefits more from ablative laser resurfacing than a peel, even
a deep one.
Epidermal peels and peels to the dermoepidermal junc-
tion and the papillary dermis do not usually cause the pores
to dilate. On the contrary, more often than not, they tighten the
pores.
PURPURA, PETECHIAE
Petechiae are small skin hemorrhages characterized by tiny
bright red, purple, or bluish spots that range in size from a pin-
point to several millimeters in diameter. They are caused by the
rupture of small, dermal blood vessels and the extravasation
of red blood cells. Purpura, unlike a telangiectasia, does not
blanch when pressed with glass. Vitamin C and K deficiencies
promote petechiae. Purpura usually tends to fade slowly and
gradually, but recurrent purpura can leave spots of iron deposit
on the skin. It is a rare complication, but petechiae can appear
rapidly after a phenol peel if the patient has bouts of severe
coughing or vomiting that trigger a sudden increase of pres-
sure in the dermal blood vessels that have been damaged and
temporarily dilated by the inflammatory reaction to the phenol
peel (Figure 37.63).
Treatment is essentially preventive and consists of
avoiding movements or maneuvers that might increase cap-
illary pressure in the facial blood vessels: coughing, vomit-
ing, and even—as the author was told recently—washing
the hair with the head bent forward or nighttime scratching.
Some herbal medicinal plants may be fairly effective and are
mainly used to treat venous stasis: witch hazel, horse chest-
nut, and red vine can increase resistance in the vessel walls
and reduce their permeability, and have an anti-inflamma-
tory and anti-edema action. These plant extracts can be taken
by mouth, and vitamins C and K can be prescribed at the
same time.
BENIGN NEVOID HYPERPIGMENTATION
Although phenol peels have been described as a possible treat-
ment for nevi,129 benign nevoid hyperpigmentation can develop
after a phenol peel (Figure 37.64). After a period of depigmen-
tation of approximately 6–8 weeks, some nevi might become
hyperpigmented. This hyperpigmentation is benign. No skin
cancer potentially induced by peelings has been reported in
medical publications.
(b)
(a)
Figure 37.61  (a) Demarcation line 1 month after a full-face phenol peel (Lip & Eyelid Formula). (b) Same patient 4 months after the peel:
the demarcation line is fading.
Go to 1 cm beyond
the hairline
Treat the
trages and
earlobe
Do not forget
the nostrils
Treat the
eyebrows
against the
lie of the hair
Go to 1cm
into the
red lip
Phenol: set
the lower limit
with patient
upright
Figure 37.62  Areas at risk of a demarcation line.

370      Textbook of Chemical Peels
(b)
(a)
Figure 37.63  (a) Localized phenol on the upper eyelid, on day 11. Normal healing. (b) Appearance of petechiae on the morning of day 15.
(b)
(a)
(d)
(c)
Figure 37.64  (a) Before a full-face Lip & Eyelid peel. (b) Thirty days after full-face Lip & Eyelid: the nevi have become depigmented.
(c) Four months after full-face Lip & Eyelid: the nevi have become hyperpigmented. (d) Six months after full-face Lip & Eyelid: the nevi are
still hyperpigmented.

Complications of chemical peels      371
NOTES

1. Heart, liver, kidney, larynx, neurological, digestive complica-
tions, and so forth.

2. TCA in aqueous solution and standard phenol formulations, for
example.

3. Preparation is usually unnecessary before Easy TCA and not
advised before Easy Phytic Solution.

4. Easy TCA to cloudy-white frosting.

5. Although this “rest” time varies considerably.

6. Schmitt D. Biologie de la peau. Les éditions INSERM, 1995.

7. Litton C, Trinidad G. Complications of chemical face peeling as
evaluated by a questionnaire. Plastic and Reconstructive Surgery.
1981; 67: 738–43.

8. Easy Phytic Solution is a slow-release and self-neutralizing
mixture of AHAs that work gradually and is not therefore com-
patible with any preparation technique that might increase the
permeability of the stratum corneum.

9. Beware of young patients who overuse aggressive anti-acne
preparations.
10. Except for skin that is badly sun damaged, as the area treated
with phenol will have completely regenerated and will be of far
better quality than the untreated, neighboring skin, which will
still look old.
11. With less than a week in between for Easy TCA.
12. See the photographs in the section on hyperpigmentation later in
this chapter.
13. Renutriv ACE Lipoic Complex (see Chapter 3).
14. Rubin MG. Manual of Chemical Peels, Superficial and Medium Depth.
Philadelphia: Lippincott, 1995.
15. It is preferable to use partially insulated needles, such as
Kobayashi.
16. There is an overall increase in the quantity of newly synthesized
DNA in the epidermis.
17. It should be remembered that any peel removes at least the
stratum corneum, the first UV barrier. Effective sun protection
should be used to make up for the loss of the stratum corneum.
18. This is partly what Easy TCA postpeel cream is for: it penetrates
more easily when it is applied immediately after the peel solution
and scavenges the free radicals as soon as they are produced. In
Easy Phytic Solution, phytic acid, with its 12 free-electron-bind-
ing sites, plays this role.
19. Grenz is the German word for “border”: the border between the
dermis and the epidermis.
20. Easy TCA does not cause hyperpigmentation when it is applied
to the Grenz zone, because of the anti-free-radical, anti-inflam-
matory, and tyrosinase-inhibiting action of the postpeel cream,
applied immediately after the acid solution. Weekly repetition of
Easy TCA is also a contributing factor to avoiding post-inflam-
matory hyperpigmentation.
21. Epidermal sliding: the acids coagulate the proteins that bind the
epidermis to the dermis and the epidermis slides over the dermis.
Sliding is the pathognomonic sign of a peel to the papillary dermis.
22. Whereas with a superficial peel, they are stimulated indirectly.
23. Manquat A. Traité Élémentaire de Thérapeutique de Matière Médicale
et de Pharmacologie. 5th ed, tome 2. 1903: 193.
24. For example, a patient with light skin with a dark-skinned parent
or grandparent. The patient’s skin appears not to react much to
inflammation, but he or she can soon develop pigmentary changes.
25. Easy TCA or AHAs can, on the other hand, be applied in cases of
standard papulopustular acne.
26. Girond JP, Mathé G, Meyniel G. Pharmacologie Clinique. Expansion
Scientific Français, 2003: 1590–1.
27. Some formulations do require this kind of manual abrasion in
immediate preparation for peeling.
28. It is not uncommon for the patient to phone the doctor complain-
ing that their melasma has gone from brown to almost black
during the first 3 days after Easy TCA. This is not a pigmentary
change but normal local dehydration of the epidermis, a sign of
a positive effect on the pigmentation problem being treated.
29. Fouque L, Seban D. Peelings associé TCA et acide glycolique.
18th réunion du GRCD, Perpignan, 25–27 Septembre 1995.
30. Cortez E. Chemical face peeling. Otolaryngology Clinics of North
America. 1990; 23: 947–60.
31. The Wood’s lamp (350–390 nm) can, however, reveal intraepider-
mal pigmentation that is lying over another dermal pigmenta-
tion. In this case, it gives a false sense of safety, and there is a risk
of promising the patient rapid results when only the epidermal
pigmentation can be readily eliminated.
32. JAMA. 1956; 162(10): 974–5.
33. Kenney JA, Grimes PG. How we treat vitiligo. Cutis. 1983; 32:
347–8.
34. A cream with a concentration of 20% is used (ICN pharmaceu-
ticals, Costa Mesa, CA, USA). In the case of resistance, the der-
matology department at Yale University School of Medicine uses
concentrations of up to 40%.
35. For example, if the product is applied at night, there is a risk
of depigmenting other parts of the body through involuntary
movements when asleep or by rubbing the eyes with the hand
while applying the treatment, etc.
36. Hedges TR, Kenyon KR, Hanninen LA, Mosher DB. Corneal and
conjunctival effects of monobenzone in patients with vitiligo.
Archives of Ophthalmology. 1983; 101: 64–8.
37. Nordlund JJ, Forget B, Kirkwood J, Lerner AB. Dermatitis pro-
duced by application of monobenzone in patients with active
­vitiligo. Archives of Dermatology. 1985; 121: 1141–4.
38. Catona A, Lanzer D. Monobenzone, superfade, vitiligo and con-
fetti-like depigmentation. Medical Journal of Australia. 1987; 146:
320–1.
39. Pheomelanin is lighter than eumelanin.
40. Glycolic acid + lactic acid + mandelic acid + phytic acid in a slow-
release solution that does not need neutralizing.
41. Five days after Unideep; 7 days after TCA in aqueous solution.
42. Inhibition of homogentisic acid oxidase, leading to local accu-
mulation of homogentisic acid followed by polymerization that
forms the “ochronotic” blue-black pigment.
43. Mills OH, Kligman AM. Journal of the Society of Cosmetic Chemists.
1978; 29: 147.
44. For example, the possibility of including products in liposomes,
cyclodextrins, nanosomes, or multilayers and using specific mol-
ecules such as arbutin, magnesium ascorbyl phosphate, etc.
45. The chemical composition of the base cream can alter the anti-
bacterial effectiveness of azelaic acid: Charnock C, Brudeli B,
Klaveness J. Evaluation of the antibacterial efficacy of diesters
of azelaic acid. European Journal of Pharmaceutical Sciences. 2004;
21(5): 589–96.
46. Breathnach AS, Robins EJ, Nazzaro-Porro M, Passi S, Picardo
M. Hyperpigmentary disorders–mechanisms of action. Effect
of azelaic acid on melanoma and other tumoral cells in culture.
Acta Dermato-Venereologica Suppl (Stockh). 1989; 143: 62–6.
47. Nazzaro-Porro M. Azelaic acid. Journal of the American Academy of
Dermatology. 1987; 17(16): 1033–41. Review.
48. Mingrone G, Greco AV, Nazzaro-Porro M, Passi S. Toxicity of
azelaic acid. Drugs under Experimental and Clinical Research. 1983;
9(6): 447–55.
49. Yokota T, Nishio H, Kubota Y, Mizoguchi M. The inhibitory
effect of glabridin from licorice extracts on melanogenesis and
inflammation. Pigment Cell & Melanoma Research. 1998; 11: 355-61.
BOX 37.1
Not counting the importance of skin preparation, the adju-
vants used, technical errors, and preventive postpeel care
and treatment, the risk of pigmentary changes can be quan-
tified diagrammatically as follows:

Phenol < TCA > AHA > Easy TCA

372      Textbook of Chemical Peels
50. About 39% inhibition at a concentration of 5 × 10–5 mol/l. The
minimum active concentration in a topical application seems to
be 1%–2%.
51. Nakajima M, Shinoda I, Fukuwatari Y, Hayasawa H. Arbutin
increases the pigmentation of cultured human melanocytes
through mechanisms other than the induction of tyrosinase
activity. Pigment Cell & Melanoma Research. 1998; 11: 12.
52. At the same doses, tretinoin is more effective than retinol, but it
is also more irritating to the skin. Appropriate doses of retinol or
retinaldehyde can be just as effective as tretinoin, without being
irritating. Keratinocytes have the necessary enzyme arsenal to
convert these precursors into retinoic acid, the active molecule.
53. That is, the –C(OH) = C(OH)– part of the molecule.
54. Lee SH, Choi SY, Kim H et al. Mulberroside F isolated from the
leaves of Morus alba inhibits melanin biosynthesis. Biological and
Pharmaceutical Bulletin. 2002; 25: 1045–8.
55. Ando S, Ando O, Suemoto Y, Mishima Y. Tyrosinase gene tran-
scription and its control by melanogenic inhibitors. Journal of
Investigative Dermatology. 1993; 100: 1505–55.
56. Usuki A, Ohashi A, Sato H et al. The inhibitory effect of glycolic
acid and lactic acid on melanin synthesis in melanoma cells.
Experimental Dermatology. 2003; 12(Suppl 2): 43–50.
57. Excessive application on the doctor’s part, too high a concentra-
tion of acid, especially high permeability of the skin, etc.
58. To the papillary or reticular dermis.
59. The cells responsible for immune defense are sensitive to acids
and are destroyed by them.
60. Apart from a peel with Unna’s paste, after which hydration is not
advised.
61. Even and rapid application, neutralization before the first pin-
point frosting, except for Easy Phytic Solution, which is neutral-
ized naturally by the buffer potential of the skin itself.
62. Brigitte. 1995; 19: 62–8.
63. Which thins the stratum corneum, significantly increases epi-
dermal permeability, and makes the AHAs penetrate more rap-
idly and more deeply.
64. Water does not neutralize acids but dilutes them, which is not
enough in this case. An acid is neutralized by combining it with
a base to produce a salt.
65. Stone PhA. Peelings au phénol Baker/Gordon et modifiés. Journal
de Médecine Esthétique et de Chirurgie Dermatologique. 1996; XXII(90):
93–7.
66. 50% m/m = 50 g TCA crystals + 50 g water, whereas 50% m+v =
50 g TCA crystals + 100 ml water. In both cases, it is “50%,” but it
is clear that the first solution is far stronger than the second. See
Chapter 12 for more information.
67. In addition to TCA and water, a tamed solution contains other
ingredients that change or regulate its activity. Results are there-
fore more predictable.
68. Collins PS. Chemical face peelings. In: Elson ML (Ed.). Evaluation
and Treatment of the Aging Face. Germany: Springer-Verlag, 1995:
34–67.
69. Fintsi Y. SEMCC Conference, Sitges, Spain, April 1997.
70. Yeowell HN, Pinnell SR. The Ehlers–Danlos syndromes. Seminars
in Dermatology. 1993; 12: 229–40.
71. Drockop DJ, Kuivanieni H, Tromp G, Ala-Kokko L. Inherited
disorders of connective tissue. In: Braunwald E, Fauci AS, Kasper
DL et al. Harrison’s Principles of Internal Medicine. 15th ed. New
York, McGraw-Hill, 2001: 2290–300 (specifically 2295–7).
72. Yusel D. Was Paganini born with Ehlers–Danlos syndrome phe-
notype 4 or 3? Clinical Chemistry. 1995; 41: 124–5.
73. Byers PH. Ehlers–Danlos syndrome: Recent advances and cur-
rent understanding of the clinical and genetic heterogeneity.
Journal of Investigative Dermatology.1994; 103(5 Suppl): 475–525.
74. Lloyd J, Narcisi P, Richards A, Pope FM. A T+6 to C+6 mutation
in the donor splice site of COL31A IVS7 causes exon skipping and
results in Ehlers–Danlos syndrome type IV. Journal of Medical
Genetics. 1993; 30: 376–80.
75. Wertelecki W, Smith LT, Byers P. Initial observation of human
dermatosparaxis: Ehlers–Danlos syndrome type VIIC. Journal of
Pediatrics. 1992; 124: 558–64.
76. Clayton E, Wheeler JR. Ehlers–Danlos syndrome. In: Cecil–Loeb
Textbook of Medicine. 30th ed. 1712–13.
77. Carr AJ, Chiodo AA, Hilton JM, Chow CW et al. The clinical
features of Ehlers–Danlos syndrome type VIIB resulting from
a base substitution at the splice acceptor site of tiatron 5 of the
Col1A2 genes. Journal of Medical Genetics. 1994; 31: 306–11.
78. Mattar SG, Kumar AG, Lumsden AB. Vascular complications in
Ehlers–Danlos syndrome. American Journal of Surgery. 1994; 60:
827–31.
79. Berney T, La Scala G, Vetterel D et al. Surgical pitfalls in a patient
with type IV Ehlers–Danlos syndrome. Diseases of the Colon and
Rectum. 1994; 37: 1038–42.
80. AHAs or TCA in aqueous solution could penetrate too deeply;
phenol would certainly cause scarring. Easy TCA could possibly
be used, on the strict condition that it does not go beyond the
basal layer of the epidermis (pinpoint frosting).
81. Although some doctors like to prepare the skin.
82. As this peel is slow-release, anything that accelerates penetration
must be avoided. The AHAs in this peel build up in the stratum
corneum before being slowly released into the epidermis.
83. This type of dangerous procedure consists in reaching the limits
of a peel’s possibilities; the safety factor gets lower as the peel
gets closer to this limit.
84. A deep peel of the radial folds of the lips (Lip & Eyelid); see
Chapter 36.
85. The skin’s buffer capacity is its physiological capacity to resist
variations in pH and keep the pH stable.
86. These can form when too much product is applied at one time.
87. It mainly occurs when the doctor does not prepare the solu-
tions himself. The nurse “forgets” to mix the TCA in aqueous
­solution with the base solution and actually prepares only TCA
50% m/m for the doctor, who applies it directly to the patient’s
skin.
88. The surface to be treated should be touched in the same way as
when touching a keyboard: quickly and precisely. There is no
delete key with Only Touch.
89. Wojno T, Tenzel RR. Lower eyelid ectropion following chemical
face peel. Ophthalmic Surgery. 1984; 14: 9–12.
90. McKinney P, Zukowski ML, Mossie R. The fourth option: A novel
approach to lower lid blepharoplasty. Aesthetic Plastic Surgery.
1991; 15: 293–6.
91. Hecker D, Hacker SM, Ramos-Caro FA, Flowers FP. Temporary
ectropion due to topical fluorouracil. Cutis. 1994; 53: 137–8.
92. Ideally, of course, this dressing should be worn as a preventive
measure rather than a cure.
93. Whether it is a chemical or physical peel.
94. See Figures 37.21 and 37.22.
95. See Figure 37.23.
96. Many of the deep dermal papillae actually survive the acid
injury when it starts to affect the Grenz zone.
97. See Figure 37.24.
98. See Figure 37.25.
99. Locally, the peel is (much) deeper and the local immune defenses
are destroyed.
100. Remember, however, that some microbes are alcohol- and acid-
resistant (mycobacteria, for example).
101. LaVerme WE, Drapkin MS, Courtiss EH, Wilson RM. Toxic shock
syndrome after chemical face peel. Plastic and Reconstructive
Surgery. 1987; 80: 115–19.
102. Patients with herpes, active acne, or active seborrheic dermatitis,
for example. These disorders should be treated before the peel.
103. The rolling movement is similar to that used when rolling a
cigarette.
104. Using antibiotic creams or ointments.
105. Using a bismuth subgallate or thymol iodide powder mask.

Complications of chemical peels      373
106. McCulloch EG, Langsdon RR, Maloney BP. Chemical Peel with
Phenol. In: Roenigk RK, Roenigk HH (Eds.). Dermatologic Surgery,
Principles and Practice. 2nd ed. Oxford: Dekker, 1996: 1147–60.
107. In France, studies have revealed the presence of HSV-1 anti-
bodies in 70% of the population and HSV-2 antibodies in 17%
of subjects. Overall, 20% of subjects test positive for anti-HSV-2
antibodies in developed countries, and this rate can reach 60%
in developing countries. In France, labial herpes, or cold sores,
affect around 12 million people.
108. Only 2 cases of postpeel herpes were counted in 5280 Easy TCA
peels to the basal layer, performed in Spain, on 1320 patients,
each treated for 1 month, at all times of the year.
109. Asken S. Unoccluded Baker–Gordon phenol peels—Review and
update. Journal of Dermatologic and Surgical Oncology. 1989; 15:
998–1008.
110. Bupivacaine and ropivacaine have a much longer duration
of action than lidocaine. Ropivacaine poses a far lower risk of
­cardiac arrhythmias.
111. For example, sublingual lorazepam (Temesta) 2.5 mg of 1/2 to 3
tablets a day.
112. For example, acetaminophen plus codeine.
113. Sterile Vaseline should be applied several times a day on the
powder mask (see Chapter 35).
114. Two cases of allergy out of 5280 peels: facial edema, mild ery-
thema and pruritus, responsive to the topical application of
hydrocortisone for 2 days.
115. From Latin: redness, pain, swelling, heat.
116. Berne MB, Levy NL. Physiology. 3rd ed. Mosby Yearbook. 1993.
117. This might happen, for example, when Easy Phytic Solution
is applied to thin and dry skin. The mixture of AHAs reaches
the Grenz zone in places and can trigger a local edematous reac-
tion that looks like an allergy but disappears by itself in 48 hours.
118. This is a rare, but reported, side effect.
119. Varidase = 10 000 IU streptokinase and 2500 IU ­streptodornase.
Streptokinase is a protein, an enzyme produced by beta-­hemolytic
streptococci. It has indirect fibrinolytic properties by binding
with plasminogen. It is a fibrin nonspecific thrombolytic.
120. Small, whitish and firm formations that form epidermal cysts.
They are formed from an accumulation of keratin in the pilose-
baceous units.
121. Bismuth subgallate or thymol iodide powder mask (see
Chapter 35).
122. Easy TCA solution contains AHAs, antioxidants, vitamins, and
saponins, and can be applied on all skin types, without prepara-
tion and prior cleaning of the skin.
123. The cream does not contain any local anesthetic, however, and
its pH is slightly acidic. It therefore does not neutralize the
solution.
124. Chemical blepharoplasty is treatment of the eyelids with a local-
ized deep peel. Chemical cheiloplasty is treatment of the lips
with a localized deep peel (see Chapter 36).
125. The nucleic acids in the thymus have the same absorption curve
as the ozone layer. If there were no ozone layer, these nucleic
acids would absorb UVC, and the free-radical damage caused by
this absorption would destroy the body’s immune defenses.
126. Melablock-HSP: physical and chemical protection, SPF 50+, and
HSP inducers.
127. The possibility of using phenol as a more superficial peel has
been broached elsewhere in this book. Because of the relatively
high risk of toxicity and complications, this agent should only be
used for deep peels carried out under strict control.
128. Benatar D. Le peeling au phénol. Journal de Médecine Esthétique et
de Chirurgie Dermatologique. 1988; XV(60): 319–23.
129. Hopkins JD, Smith AW, Jackson IT. Adjunctive treatment of con-
genital pigmented nevi with phenol chemical peel. Plastic and
Reconstructive Surgery. 2000; 105: 1–11.

38
Combination peels
Chemical peels, among the most ancient cosmetic treatments,
have undergone a quick evolution during the last 20 years. The
evolution has not been based on the chemical molecules them-
selves; doctors still use alpha hydroxy acids (AHAs), trichloro-
acetic acid (TCA), phenol, or salicylic acid. The evolution relates
to the security, reproducibility, and combination of techniques.
A TCA peel, even if it reaches the papillary dermis, or
a phenol peel, even if it reaches the reticulary dermis, is not
always enough to correct the patient’s cosmetic problem, and
experienced doctors are often led to combining several tech-
niques to achieve the results patients want. Peels can be com-
bined to work together or with other surgical or nonsurgical
techniques. Using another technique or another peel before a
TCA peel is often intended to remove part of the epidermis or
to enhance penetration of TCA. The first technique provides
the equivalent of a superficial peel that will enhance the action
of the TCA applied afterward. It also might multiperforate the
skin, allowing a deeper and faster penetration of TCA. Some
authors maintain that using a combination of peels lowers the
frequency of complications compared with using more concen-
trated TCA in aqueous solution. Not all combinations are safe,
however, and a combination of different peels on the same sur-
face can make symptoms more complex and increase the risk of
complications when compared with safer formulations such as
Easy TCA or Easy TCA Pain Control.
Postpeel care is also more complex when peels are com-
bined, as the injury is deeper: 6–7 days of postpeel care are
usually required, during which the patient will use Vaseline,
antioxidant creams, or antiseptic washes (e.g., povidone–
iodine solution). Postpeel care should include a depigmenting
cream (Blending Bleaching Cream) and effective sun protec-
tion (Melablock-HSP). Prolonged erythema lasting more than
15 days is common when the peel reaches the reticular dermis.
If erythema is local or focal—and therefore suspicious—it can
be treated with a strong corticosteroid cream. The risk of scar-
ring and pigmentary changes is greater when peels are com-
bined on the same surface because of the increased penetration
of the acids. Cosmetics that are suitable for the postpeel period
should be used as soon as the skin can tolerate them. Tretinoin,
AHA creams, or benzoyl peroxide must not be used during the
6 weeks following a peeling.
SECURITY
Security is partially grounded on the correct definition of the
peel concentration. Literature about TCA reports, for example,
that a 35% TCA peel is a superficial peel, inducing poor dermal
injury. However, it depends on the way the concentration has
been calculated: in weight plus volume (w+v) or in weight by
weight (w/w), for example. For example, 50 g of pure TCA pow-
der plus 100 ml of water (which is a 50/100) is not as aggressive
as 50 g of pure TCA powder plus 50 g of water (which is a real
50%). It is evident that a 35% w/w is much more aggressive than
a 35% w+v. The security breach lies in the fact that, in medical
articles, the type of calculation is rarely indicated. Therefore,
when intending to reproduce the effect of a 35% TCA (w+v) but
using a 35% (w/w), a doctor can burn his or her patient and,
conversely, when intending to reproduce the effect of a 35%
TCA (w/w), but using a 35% (w+v), the result is insufficient
compared to the description.
Moreover, some concentration calculation techniques can
lead to concentrations higher than 100%, which is similar to
chemical heresy. To avoid misinterpretation, this chapter uses
only the w/w calculation.
Security is also founded on the regulation of postpeel
inflammatory process, responsible—if not controlled—for
many of the possible side effects. This control represented a
decisive evolution pathway beginning at the end of the 1990s.
REPRODUCIBILITY
Reproducibility, at first view, can look like a weak point of peel-
ings when compared to other techniques as physical abrasions.
The difficulty lies in the peel solution preparation: has it been
prepared w/w or w+v? Was the TCA powder used for preparing
the solution well dehydrated and not oxidized? Was the TCA
powder pure or of low quality? How can a physician reproduce
a technique described in the literature when so many param-
eters remain unknown?
Physicians have two choices: The first one, the safest, is
to use standardized solutions, manufactured under ISO 13485
rules with a controlled uniformity of product quality and solu-
tion concentrations. The second one is to use solutions prepared
by a pharmacist, but many variables can potentially reduce the
reproducibility of the results.
To allow for good reproducibility of techniques, this
chapter discusses the use of standardized solutions only,
manufactured under ISO 13485 rules. These include Skin Tech
solutions.
COMBINATION OF TECHNIQUES
It is well known that, in case of photoaging, the result of a
chemical peel will be better if the injury, and hence the repair,
is deeper. This often is not the case when treating other indi-
cations such as active acne: a deep peel could induce a severe
infection rebound, while a superficial peel will clear the skin of
its impurities.
When a deep action is needed, physicians have two
options: increase the peeling agent concentration (deeper
peels) or combine several techniques (combination techniques).
Increasing the peeling agent concentration is not a magic potion
for a better result. A too high concentration of not partially neu-
tralized AHAs, if acting long enough before neutralization,
will damage the skin rather than repair it. On the other hand, in
the author’s experience, a high TCA concentration peel does not

Combination peels      375
repair the skin as well as a phenol peel does, even if the depth
of injury and repair is histologically the same.
Because increasing concentration does not solve the prob-
lem, the best choice for deepening the peeling action is to com-
bine techniques. Doing so results in a better depth of action
without increasing the risk of side effects.
Depending on the peel solution and technique used,
many combinations are possible.
THICK SKIN OR THIN SKIN
Patients with thin and sensitive skin (Figure 38.1) are often not
the best candidates for a combination peel because the skin’s
permeability is high already, allowing a fast and deep penetra-
tion of peelings agents. Increasing the skin’s permeability by
using combination techniques could lead to long-term ery-
thema or even scarring if the skin regeneration potential is sur-
passed by the use of a technique that is too aggressive.
Patients with thick and oily skin (Figure 38.1), and acne
scars, are much better candidates for combined techniques.
Their skin is resistant to acids, and a combined technique may
allow results that would have been impossible with a simple
technique.
The doctor can use a simple pinch test to check the
patient’s global skin thickness, but this is not a definitive test
for determining acid penetration because it mainly measures
dermal thickness. Nevertheless, thin skin as measured by a
pinch test usually exhibits faster frosting than thick skin that
is more hydrated and young.
SKIN CONDITIONING AND POSTPEEL
CARE: GENERAL RECOMMENDATIONS
Patients at any risk of postinflammatory hyperpigmentation
(PIH) should prepare for a peel by using Blending Bleaching
Cream
(containing
anti-tyrosinases,
antioxidants,
anti-­
dopachrome tautomerase, anti-melanin polymerization, etc.),
hydroquinone (which is mixed with the Blending Bleaching
Cream just before application), and/or tretinoin cream.
Fitzpatrick phototypes V or VI need tougher prepeel condi-
tioning to prevent postpeel (PIH). The higher the patient’s risk
for PIH, the longer the prepeel conditioning period should be.
Tretinoin cream (0.5%) can be used for thick-skinned patients
and when there is a need to speed up the postpeel healing
time; tretinoin speeds up epidermal turnover and therefore
epidermal regeneration when used before a peel but tends to
slow down skin healing when applied during the recent post-
peel period. Degreasing the skin with acetone or disinfecting it
using alcohol on swabs could cause microwounds on the skin,
possibly allowing a too deep penetration of both acids applied
after the skin conditioning. Therefore, the use of alcohol or ace-
tone should be avoided before combination techniques. Instead,
the skin should be washed using a soft sponge, water, and anti-
septic soap or antiseptic solution, without too much pressure.
The skin should then be rinsed with water and gently dried.
Caring for the skin after the peel depends on the type of
injury, but in any case, patients should not scratch, remove dead
skin, or provoke any aggression to the skin. After a deep peel,
the patient should carefully wash and disinfect his or her hands
before touching the treated skin.
Peels to the Grenz zone or entering the papillary dermis
do not need complex postpeel care. Papillary dermis immuni-
tary cells are not killed by the acid, and the epidermis is not
physically removed from the skin that still is protected by this
layer. Even a dead epidermis represents one of the best protec-
tive dressings.
Oil in water moisturizers and Blending Bleaching Cream
should be used as soon as possible, as long as these creams do
not induce any burning sensation. If the patient experiences a
burning sensation after applying these creams, delay the cream
application for few days. The patient’s hands must be disin-
fected before he or she touches the skin. Starting on day 2, the
skin can be washed with a gentle cleanser (Skin Tech Cleanser
>1 cm: Thick
Foresee a slow penetration
>1 cm: Thin
Foresee a fast penetration
(a)
(b)
Figure 38.1  (a) Thick skin (>1 cm); (b) thin skin (<1 cm).

376      Textbook of Chemical Peels
foam, pH balanced at 5.5) before every cream application, four
times a day. Petroleum jelly (Vaseline) can be applied if the
patient experiences very dry skin. Vaseline could trigger acne
by occlusive effect, so patients should not use it over too long a
period of time.
At the end of first week after the peel, reepithelialization
is usually complete and the patient should use creams to pre-
vent PIH (Blending Bleaching Cream, eventually mixed with
hydroquinone cream), or any other cream that suits the patient
(tensing cream with DMAE, etc). The patient can use makeup
beginning on day 7 and must apply sunscreen three times a day
as soon as possible after the peel. In case of erythema, the patient
can use IPLase cream to reduce erythema and inflammation.
PEELS THAT DESTROY THE FULL
PAPILLARY DERMIS OR ENTER THE
SUPERFICIAL RETICULARY DERMIS
In this case, postpeel care is very important because there is a
higher risk of infection, slow healing, and scarring. At the end
of procedure, postpeel mask cream is applied and then covered
by bismuth subgallate powder (which is not soluble in water) to
create a “yellow mask.” The exterior of the mask is dry, but the
interior remains naturally moist and protected from injury and
infection. This protective yellow mask should not be removed,
picked at, or scratched for any reason during the first week—
there is no good indication for removing it. On the first day after
the peel, the patient should simply add a bit of yellow powder
if the mask becomes wet (it becomes greenish in this case). The
patient does not have to do anything else until day 3. On day 3,
the yellow mask will begin to crack. The patient should visit the
doctor, who will check for signs of infection and apply Vaseline
on the edges of the powder crust. On day 6, the yellow mask is
ugly, with a yellow-green color and darker areas of cracking;
the doctor will again check for signs of infection and gently
massage Vaseline on the entire treated are. Vaseline creates an
impermeable coating that will prevent transepidermal water
loss evaporation. The excess water that accumulates under the
nonsoluble mask will automatically pull away the yellow crust,
which eventually will fall off. The skin should be reepithelial-
ized at this time. If there is no reepithelialization, the doctor
should consider the possibility of infection and give the patient
oral antibiotics or antiviral molecules. Mycotic infections also
should be considered.
REDNESS
Deep procedures often result in postpeel redness, whose dura-
tion often depends on the depth of the procedure and the qual-
ity of postpeel care. The author recommends applying IPLase
cream to the treated area three to four times per day, to alle-
viate the redness. Though it does not contain nonsteroidal
anti-inflammatories (NSAIDs) or corticoids, it has a marked
anti-inflammatory and antiredness effect that is more effective
than other posttreatment creams. IPLase also has been success-
fully used to reduce radiodermitis when applied before and
after radiotherapy for breast cancer. One or two weeks’ appli-
cation is usually sufficient to reduce redness. In cases of deep
redness, a longer application should be considered.
General redness of the treated area is not considered a
side effect but is the normal postpeel appearance, and a sign
of vascular rebuilding. Such redness could last 3 months or
more, depending on the depth of the combination used. Local
redness, if associated with local edema, may result from local
overpeeling at risk of scarring reaction and treated as it is con-
venient to do.
SUN PROTECTION AND AVOIDANCE
There is no good sun protection without sun avoidance. Sun
protection is critical after every peel.
A patient who has undergone an intraepidermal peel
must apply SPF 30 sunscreen daily (at 9 a.m., 12 p.m., and
3 p.m.) for 2–3 weeks, depending on his or her skin type and
level of sun exposure.
After a deep reticulary dermis peel, the patient must
apply a SPF 50+ sunscreen daily (at 9 a.m., 12 p.m., and 3 p.m.)
for 3 months, and then SPF 30 daily (at 9 a.m., 12 p.m., and 3
p.m.) for 3 more months. This equates to total sun avoidance
for 3 months and reasonable sun protection for 3 more months.
Sunbathing and the use of tanning beds are prohibited for 1
year. Some deep procedures using classical phenol in water and
alcohol formulas could completely inhibit melanin production
by the melanocytes and impose lifelong sun avoidance.
Sunscreen products could induce a burning sensa-
tion on newly peeled skins. In this case, their use should be
delayed for few days and the patient should avoid any expo-
sure to the sun.
COMBINATION OF DIFFERENT
CONCENTRATIONS OF TRICHLOROACETIC ACID
It is common to combine different concentrations of TCA dur-
ing the same peel session: a TCA peel to the papillary dermis
(Unideep) can be applied locally for dermal melasma on the
forehead, for example, while a TCA peel to the Grenz zone
(Easy TCA classic or Pain Control) is applied to the rest of the
face (to even out the results) after focal treatment of keratoses or
lentigines with a TCA peel to the reticular dermis (Only Touch).
See Figures 19.4, 19.8, 22.8, 22.12, and 22.16.
PHENOL PLUS TRICHLOROACETIC ACID
Using peels to different depths on the same patient is indi-
cated when disorders of different depths coexist. Consider a
patient who presents with early elastosis, a few lentigines, and
deep wrinkles on the upper lip: only phenol can get rid of the
wrinkles on the upper lip (see Figures 26.1, 30.14, 30.20, 30.21,
36.3–36.20) but it would be unnecessarily deep to treat the early
elastosis on the rest of the face. The phenol would eliminate
the few senile lentigines, but a deep and very localized treat-
ment with Only Touch can also eliminate them and with less
risk. This patient would therefore benefit from the combination
shown in Table 38.1 (see also Figure 38.2).
REPETITION OF COMBINED PEELS
Combined peels usually reach the dermis. As mentioned, the
papillary dermis is easily reached, but it is also possible to
reach the reticular dermis using more aggressive combinations
locally. This type of peel cannot be repeated until the skin has
completely recovered, and not before 3 months. Any persistent
erythema, a sign of even the slightest inflammation, rules out
another peel.
TYPES OF COMBINATIONS
Penetration Enhancement Combinations
For deeper penetration, a peel solution can be combined with
another technique or another peel. The result should be better

Combination peels      377
dermal fibrosis, improving the skin tension. Several types of
peels are typically combined—usually to treat a full area such
as the face, hands, or décolletage—to enhance the penetration
of the peeling agent in the last coat without increasing acid con-
centration. The final result is deeper wound regeneration with-
out an increase of side effects. The most popular combinations
are AHA before TCA, Jessner before TCA or AHA, fractional
laser before TCA, microneedling before or after TCA, and abra-
sion before or after TCA or after phenol.
Mosaic Peels and Pixel Peels
These are a combination of different depths of peels in the same
session. The term mosaic is used when large areas are deeply
treated, and the term pixel is used when small areas (usually
smaller than 1 cm diameter) are deeply treated.
Some areas will be deeply treated primarily to remove
local wrinkles or deep lentigines, while other areas will be
treated more superficially at the same time, during the same
peeling session, primarily to balance the result on photoaged
skin. If an area of the face is severely affected by wrinkles but
the rest of the face has a relatively good appearance, it is not
necessary to subject the patient to a full-face deep peel when a
local deep peel can sufficiently resolve the problem. The local
deep peel will be done in combination with a more super-
ficial peel on the rest of the face to balance the final result.
This technique is often used in chemical blepharoplasty and
chemical cheiloplasty. A local, very deep phenol peel (a deep
reticulary dermis peel) is combined with a full-face light phe-
nol peel (papillary-reticulary dermis interface) or even with an
uncomplicated basal layer TCA peel if the photoaging is not
too noticeable. When some large lentigines stain the skin, it is
not always necessary to perform a medium or deep peel on the
whole face, décolletage, or hand, and it is safer to use the pixel
peel technique. This allows the physician to deeply treat a len-
tigo very locally and to apply a uniform peel around the deeply
treated area.
Combination of Peels and Other Nonabrasive
or Perforating Aesthetic Procedures
In this case, techniques are combined to obtain different types
of results and not to obtain stronger results. Fillers, mesother-
apy for biorevitalization, botulinum toxin, and many more
methods can be combined with some peels.
PENETRATION ENHANCEMENT COMBINATIONS
The corneal layer is the main barrier for any product applied
on the skin and also for wounding agents penetration: remov-
ing, damaging, or multiperforating horny layer induces faster
and deeper penetration of the peel agent. Corneocytes may be
thought of as the plasticized cover of a book that protects the
internal pages—keratinocytes, in this comparison—against
external aggressions. The literature first described techniques
that combined one weak wounding agent (AHA or salicylic
acid) to weaken the permeability of the epidermis and allow
a deeper penetration of a stronger peeling agent, TCA, applied
after the injury.
Combination of Alpha Hydroxy Acids and TCA
The most efficient and well-known AHA is the shortest one:
glycolic acid. Glycolic acid can be used in several concentra-
tions, and at several pH levels. The strength of a glycolic acid
peel depends on its concentration and pH, but its action also
depends on the application protocol. The doctor cannot deter-
mine the potential of an AHA peel by simply asking about its
concentration or its pH.
A 70% (w/w), pH 1, glycolic acid in water solution induces
a stronger effect than a 50% (w/w), pH 1, as long as the 70%
is not neutralized more quickly than the 50%. Neutralization,
which immediately catches the protons circulating freely in
the solution (which are the only active ones), also immediately
halts the abrasive effect of AHA peels: the faster the peel is neu-
tralized, the lower the chance for a proton (H+) to be effective.
In fact, the proton (H+) is consumed by a basic product dur-
ing the neutralization reaction and transformed in water in the
irreversible reaction (glycolic-H+) + (NaOH) -> (glycolate-Na) +
H2O. The physician must understand the power of tap water:
rinsing the skin with water at the end of a peel does not neu-
tralize AHAs, but dilutes the solution from 70% up to a non-
aggressive%, depending on the added quantity of water.
Table 38.1
First
session:
Com­
bined
peels
1. Application of Lip &
Eyelid Formula
(occlusive protocol)
On the upper lip
2. Immediately
followed by an
application of Only
Touch peel
On the lentigines
3. Application of Easy
TCA
To the whole face, except
for the area treated with
phenol
8 days later:
Second Easy TCA
Application to the Grenz
zone (cloudy-white
frosting) on the entire
face, except for the area
treated with phenol
8 days later:
Third Easy TCA
Application to the Grenz
zone (cloudy-white
frosting) on the entire
face, except for the area
treated with phenol
8 days later:
Last peel
session
If the lentigines have not completely disappeared,
Only Touch is reapplied locally.
A fourth Easy TCA is then applied to the Grenz
zone (cloudy-white frosting), except for the area
treated with phenol.
Depth of injury
3–5 seconds
5–8 seconds
8–15 seconds
Figure 38.2  Graph representing how to combine different types
of peels and the interval for repeating the peels. Local phenol is
applied first (e.g., on the upper lid). Immediately after, Only Touch
is applied to treat lentigines. When local frosting due to the deep
TCA (Only Touch) is achieved, Easy TCA is applied to the entire
face, except the phenol-treated area.

378      Textbook of Chemical Peels
AHAs are used in combination techniques because
they are well known as desmosomes’ “chainsaw,” inducing
a peel by cutting the links that join corneocytes or keratino-
cytes together. At the same time, skin permeability is much
improved, and applying a TCA peel after a glycolic acid peel
deepens the effect of the TCA. Concentrations therefore have to
be adapted in combinations.
Indications
A combination peel (glycolic + TCA) obtains good results on
fine lines, freckles, lentigines, and keratoses—for example,
when a peel such as a 20% to 25% w/w TCA solution (Unideep
23% w/w TCA) is used after a 70% native glycolic acid peel.
Freckles, small lentigines and keratoses, and epidermal and
Grenz zone pigmentation are largely improved when a peel
such as Easy TCA (15% w/w TCA) is used after glycolic acid.
Acne scars, deep wrinkles, folds, and sagging skin are
not good indications for this technique because these patholo-
gies require a reticular dermis deep peel.
Protocol for Application
Apply Glycolic Acid  Glycolic acid 70%, not buffered (native
pH 1) is segmentally applied on the skin, using a cotton ball
or any convenient applicator. Depending on the skin thickness
and oiliness, several coats might be needed to induce the first
erythema, which is a sign of the epidermal action of the glycolic
acid and the end point of this part of the peel.
Rinse the Glycolic Acid  As soon as erythema is apparent, the
glycolic acid has to be rinsed with a large quantity of water,
but it should not be neutralized. The use of a neutralizer
would transitorily modify the skin pH and “pre-neutralize”
the TCA that will be applied just after the AHAs. Rinse until
the patient declares that he no longer feels a burning sensa-
tion. Be cautious if some frosting points have appeared: the
TCA penetration will be faster on this area. After rinsing, dry
the skin using soft gauzes that do not induce any mechanical
abrasion.
Apply the TCA Solution
After rinsing the AHA peel and depending on the needed peel
depth, the author might combine two different TCA peels with
standardized w/w concentrations: Easy TCA 15%, normally
used for inducing a peel up to the basal layer or the Grenz
zone, or Unideep 23%, usually applied when a peel up to the
papillary dermis is needed. Easy TCA 15% TCA is preferred
for nonfacial skin (including the neck) because body skin could
experience unexpected reactions when combining higher con-
centrations. The face can tolerate a 20% TCA (w/w) after gly-
colic acid. If the doctor selects a stronger TCA concentration,
he should be very careful during the application, checking
individual responses on small areas. The depth of skin injury
and regeneration depends on the transepidermal penetration
(how permeable the skin is) and also on the number of coats
that are applied: more coats give a deeper peel. Knowing that a
previous application of glycolic acid will deepen the TCA pen-
etration, the selected TCA peel will be applied the same way
as usual, but the doctor will wait for a different end point. For
example, after a few minutes, the first coat of Easy TCA will
easily induce a peel up to the Grenz zone (end point: frost-
ing clouds), and Unideep will induce a uniform pink-white
frosting.
Remember that TCA is a one-way peel: after penetration
into the skin, and skin protein coagulation, the peel cannot be
reversed. Excess TCA should not be applied because the intent
of neutralization can only neutralize the TCA that did not yet
penetrate the skin and still floats on it. The frosting itself cannot
be neutralized, because it represents the clinical symptom of
coagulated, destroyed proteins that cannot be repaired by the
simple use of a base such as sodium bicarbonate.
Rinsing the skin with water would remove only the excess
TCA that floats over the skin and not the TCA that already pen-
etrated the skin.
End of Procedure
During a peel, primarily during TCA application, patients expe-
rience a burning sensation, which is stronger after Unideep 23%
than after Easy TCA 15%. The standard recommendation is to
use a fan or to apply cold packs to relieve the burning or sting-
ing pain, but for some patients these methods offer little relief.
Fortunately, both include a postpeel mask cream that is applied
on the face immediately after the frosting has appeared and
that nearly immediately suppresses the pain and inflammatory
reaction. The postpeel mask has to be applied only once, by the
doctor, immediately at the end of the peel. It is not a neutralizer
and stays on the skin until the next morning, when it is washed.
How to Increase the Peeling Depth
Increasing the TCA concentration could be an option, but a
potentially dangerous one in this case. Degreasing the skin
with acetone or disinfecting it with alcohol, using a swab for an
application with friction, will deepen the penetration.
The uniformity of the frosting also depends on the uni-
formity of the glycolic acid penetration. Some areas need more
TCA applied locally: on keratoses or large lentigines. One more
local touch after the end of the peel will give a focal deeper peel
that results in redness that can last for weeks, and the skin has
to be protected from the sun. Microneedling with a stamp, after
TCA application, can also deepen the penetration of acids.
Postpeel Treatment
See the general recommendations in Chapter 3, depending on
the depth of the combined peel.
Carbon Dioxide Application Followed by TCA Peel
Carbon dioxide applied on the skin disrupts its natural perme-
ability and allows TCA solutions to penetrate deeper and faster.
The depth of the wound caused by the cold directly depends on
the contact time: 2–5 seconds of contact is considered grade 1 (2
seconds on thin skin and 5 seconds on thick skin), 4–8 seconds
as grade 2, and 9–15 seconds as grade 3.
This combination technique induces a strong inflam-
matory reaction, and therefore there is a high probability of
PIH. The patient’s skin must be perfectly conditioned before
the peel, and phototypes higher than IV should not be treated.
Phototype IV patients have to be treated cautiously, due to the
high risk of PIH.
Technique
Preoperative Points  The patient can take one acetaminophen
and codeine tablet 30 minutes before the procedure to reduce
discomfort. Skin disinfection (alcohol) and degreasing (ace-
tone) should be performed. A majority of patients appreciate
the presence of a fan because it helps evaporate the acetone and
alcohol vapors.

Combination peels      379
Carbon dioxide exists under pressure in special canisters
from which it is easy to extract a solid block, pencil shaped.
Carbon dioxide would stick to the skin if directly applied to it.
Therefore, the block is usually dipped in a solution (2/3 acetone +
1/3 alcohol) so that it will slide on the skin.
Carbon dioxide is primarily applied to small areas that
need deeper TCA penetration. It is rarely used on large areas
because fractional lasers, skin abrasion techniques, or micronee-
dling devices can be used instead, with many advantages.
Carbon Dioxide Application
•
Acne scars: Grade 3 application (insisting even on the
edges of scars to smooth them).
•
Seborrheic/actinic keratoses: Grade 2 application.
•
Perioral wrinkles: Grade 2 application.
•
Periocular wrinkles: Grade 1 application.
TCA Application  After application of carbon dioxide, the skin
is dried with a gauze and TCA is applied uniformly. We are
used to apply TCA soaked on 2 cotton buds. Easy TCA (15%
w/w) or Unideep (23% w/w) can be safely applied after carbon
dioxide. The peels reach the papillary and reticular dermis,
respectively. Higher concentrations should be used cautiously
(mainly in case of deep acne scars or thick keratoses) because
the risk of scarring (primarily hypertrophic, since atrophic
scars occur only for still deeper wounds) increases with the
TCA concentration. The author prefers to apply TCA in two
passes rather than increase the TCA concentration.
Jessner Peel followed by TCA Peel or AHA Peel
Jessner solution (also called Coombe’s solution) formula:
R/Resorcinol, 14 g
Salicylic acid, 14 g
Lactic acid, 14 g
Ethanol 95ºad, 100 ml
Jessner’s solution should be stored in a sealed brown
glass vial. It can be stored in the refrigerator for more than 2
years. The oxidation of the solution results in a pinkish color.
Contact with the nails can discolor it and result in a yellow-
orange color. The depth of Jessner solution is modulated
by the number of coats. One coat induces a very superficial
peel, while three or four coats can remove the full epidermal
thickness.
Jessner before an AHA Peel
AHA peels are known for not having a uniform penetration.
Jessner peels can improve the penetration of AHAs through the
skin and make it more uniform. Moy described the following
technique: After preparation and conventional cleaning of the
skin, apply Jessner’s solution up to “level 1”: only one coat is
applied. A rash appears, accompanied by at most a few points
of localized frosting. In the case of thick and oily skin, several
coats can be applied, using a brush, cotton buds, or any applica-
tor that suits the doctor. Allow 5 minutes between each layer.
Then apply the final coat. No neutralization is needed, but the
white coating on the skin created by salicylic acid can be gently
removed or washed with water before drying the skin and apply-
ing TCA solution. Jessner will disrupt the epidermal imperme-
ability and allow a faster and deeper pass of the AHA solution.
Selection of glycolic acid concentration (from 50% to 70%; from
pH 1 to pH 2.5) follows the security rules described earlier in
this chapter. Apply the glycolic acid solution uniformly until
erythema appears, and then neutralize.
The problem with this combination is that, classically, gly-
colic acid should be neutralized as soon as erythema appears.
Unfortunately, preexisting erythema due to Jessner’s solution
does not allow the doctor to correctly estimate the evolution
of AHAs and frosting, and unexpected overruns are common.
This technique, although more difficult, could be used in the
treatment of very oily and thick skin, which is resistant to sig-
nificant concentrations of AHA left in place for long periods
before neutralization.
Note:  The author stopped using this difficult technique and
replaced it with the use of Easy Phytic Solution, which is a 60%,
pH 1 mixture of lactic, glycolic, and mandelic acids together
with phytic acid. The solution is slow-release, allowing the
progressive and harmless actuation of 100% of the molecules
of the peeling solution. The solution is also self-neutralizing,
preventing any mistakes about the right moment to neutral-
ize. The application protocol, linked to clinical signs, allows
an easy penetration up to the basal layer in every skin type,
without any possibility of error. With Easy Phytic Solution, no
prepeel conditioning should be done, because the full integrity
of the horny layer is needed to allow the slow-release penetra-
tion. Removing the full stratum corneum would induce a too
fast penetration of this specific solution, increase the risk of
side effects, and impose a neutralization that normally is not
needed.
Jessner before a TCA Peel
Jessner’s solution can be used as preparation for a TCA peel.
Monheit describes the following technique: After preparation
and conventional cleaning of the skin (alcohol and acetone),
apply Jessner’s solution up to “level 1.” Only one coat is applied.
A rash appears, accompanied by at most a few points of local-
ized frosting. For thick and oily skin, several coats can be
applied, using a brush, cotton buds, or any applicator that suits
the doctor. Allow 5 minutes between each layer, and then apply
the final coat. No neutralization is needed, but the white coat-
ing on the skin created by salicylic acid can be gently removed
or washed with water before drying the skin and applying TCA
solution. Jessner will disrupt the epidermal impermeability and
allow a faster and deeper pass of the TCA solution. Following
the same logic as for TCA combined with glycolic acid, Easy
TCA 15% or Unideep TCA 23% can be selected, depending on
the final depth desired by the doctor.
Apply the selected TCA solution that penetrates faster—
and more evenly when thick, oily skin is treated—due to the
rupture of the effectiveness of the epidermal barrier. Penetration
will cause the patient more pain than usually. This technique
could be used for patients with oily and thick skin for whom
better penetration of TCA is needed.
Immediately after the frosting of the TCA peel has
appeared, apply the postpeel mask from the Easy TCA or
Unideep peel kit, in the needed quantity (see dosing card) to
relieve pain and inflammatory reaction. The postpeel mask
should remain on the skin until the next morning; then it is
washed and emollient, nourishing, depigmenting creams are
applied.
Note:  The author stopped using this technique many years ago
because easier and safer techniques exist.

380      Textbook of Chemical Peels
Laser Pixel Peel or Frax-Peel: Combination
of Fractional Laser and TCA
Definition
Laser ablative techniques, as well as chemical peels, are widely
used for the treatment of aged skin. The onset of laser abla-
tive treatment has brought much hope to the medical field.
The results of deep treatments using ablative CO2 lasers have
reached the histological level of phenol peels on local areas such
as wrinkled lips. Nevertheless, with the exception of upper-lip
wrinkle treatment, ablative CO2 laser results could not be easily
of the level of the ones obtained when using deep phenol peel-
ings for treating photo-damaged skin. In addition, the early
enthusiasm for laser treatments often made doctors forget the
risks of significant thermal damage suffered by tissues and the
skin’s reaction to this injury. The intellectual interest in the dis-
covery of a new technology, and the hope of patients, have over-
shadowed the risks of the method, and many side effects have
been reported. As with peels, there is a relationship between
the laser’s depth of action, the results, and the risks associated
with treatment. On the other hand, it is impossible to easily
evaluate the number of calories transmitted to the deep der-
mis and to visualize in real time the collateral damage created
around the target depth.
The risk of unwanted adverse reactions such as long-term
residual erythema, PIH, pain, infection, and scars soon made
ablative lasers much less attractive. Technological advances
and adaptation to lasers of the old technique of microneedling
then made possible the launch of the fractional laser. The frac-
tional laser’s beam is divided into many narrow beams. This
pixelated ablation does not remove a large surface of skin but
induces deep and narrow wells of coagulation. As long as a
large surface of skin is not ablated, skin regeneration is much
faster and results in fewer problems. At the same time, dermal
stimulation and therefore skin tension occur all around the
penetration wells. The same happens when using the pixel peel
technique.
The fractional laser has revolutionized skin resurfacing
treatment: significant clinical results (but not as good as full
ablative techniques) can be obtained, with a lower risk of side
effects. The Er:YAG fractional laser appears to be the best laser
for reducing wrinkle and pore size and for improving skin tex-
ture and acne scars. Hyperpigmented lesions do not seem to
be a good indication for the fractional laser, because the mela-
nocytes that have not been killed in the “penetration well” are
stimulated by the temperature shock and subsequent inflam-
mation and could trigger PIH. The pixel peel technique has to
then be adapted to the Er:YAG fractional laser. Dr. Han (Korea)
speculated a combination treatment of the Er:YAG fractional
laser (Dermablate Effect) and Easy TCA peel, taking advantage
of the unique features of each treatment method. The deep laser
stimulation wells done with the Er:YAG fractional laser are com-
bined with a basal layer (frosting points) peel using Easy TCA.
The Easy TCA postpeel mask clearly stopped posttreatment
pain, inflammation, and erythema. Not only were the results of
this combination therapy better, but the risk of side effects also
has been reduced, even for patients with Asian skin.
How to Combine Er:Yag Fractional Laser with Easy TCA Peel
The laser treatment is done first, in conformity with the usual
rules. The Easy TCA peel is applied immediately after the
fractional laser treatment. The acid will penetrate the tiny
holes induced by the fractional laser and create wells of “sec-
ondary” proteo-coagulation. The “primary” coagulation was
done by the laser beams. If an anesthetic cream such as EMLA
was applied before the laser treatment, it should be carefully
removed before the peel application because its basic pH (9.4)
would neutralize the TCA peel during application. EMLA
should therefore be removed with water and soap. Then the
skin pH should be balanced again by using Skin Tech Cleanser
foam (pH 5.5) before applying the TCA peel.
Immediately after the fractional laser application, the
skin has been multiperforated, forming numerous wells made
of dead cells that do not give the skin its physiologic imperme-
ability, focally. The Easy TCA solution will pass easily through
these wells of hyperpermeability, creating secondary protein
coagulation in the proximal neighborhood of the wells created
by the laser. At the same time, the full epidermis will be treated
by TCA, which will stimulate epidermal renewal and epider-
mal turnover. This enhances the result obtained when using a
laser application only.
This combination treatment induces a strong inflamma-
tory response from the body, and the inflammatory reaction
has to be controlled to avoid a long-term vicious cycle that
could induce self-maintenance of inflammation. Self-inducing
inflammation can permanently stimulate the cells that usually
react to inflammatory situations: melanocytes. The risk of PIH
would be very high.
Fortunately, Easy TCA comes with a postpeel mask that
controls postpeel inflammation and in this case will control
the post–combined treatment inflammation. The doctor should
apply the postpeel mask immediately at the end of the peel.
The mask will quickly alleviate the posttreatment pain, inflam-
matory sensation, and redness. The mask should be applied
once only and left in place until the next morning. Then it
should washed with a soft cleanser and postpeel daily home
care can begin: Blending Bleaching Cream if there is a risk of
PIH, tensing cream with DMAE for sagging skin, and so forth.
Sunscreen is mandatory after the treatment: see the dis-
cussion of sun protection earlier in this chapter.
Overall, the combination of the Er:YAG fractional laser
and Easy TCA offers a better result, with much less posttreat-
ment inflammation and pain, and a decreased risk of side
effects.
Microneedling Pixel Peel:
Microneedling and TCA Peel
The microneedling pixel peel is a relatively new method that
consists of microperforating the skin with a handpiece termi-
nated by a “roller” supporting needles, or a “stamp” (for very
small areas) immediately before applying a TCA peel solution.
The peel solution will penetrate the wells produced by the
needles; the depth depends on the length of the needles used.
Figure  38.3 shows a microneedling roller (600 needles) and
stamp (12 needles); the needles can range from 0.5 to 3 mm long.
This treatment takes advantage of the stimulation induced by
the microneedling itself, which will be enhanced by the TCA
penetration. Unlike a conventional peel where the acid has to
penetrate evenly through the skin, up to the desired depth, a
pixel peel allows a kind of “deep microtower peel” by coagu-
lation of the walls of the wells done by the needles. It results
in deeper fibrosis induction and therefore better skin tension,
without a significant increase of epidermal damage and, if the
needles are short, without a long social eviction. That’s the
peeling corresponding to actual fractional lasers.
First rollers showed a minimal number of needles (+/-100);
actual rollers easily exhibit a large number of different needle

Combination peels      381
sizes (600 needles from 0.25 mm up to 3 mm long). AD Roll
(Aesthetic Dermal) and Skin Tech even offer a roller that
includes a stamp. When the microneedling device is applied
to the skin, the needles perforate the epidermis more or less
deeply, creating tiny holes representing a very fast track for
acid penetration but that close quite quickly.
Selection of Needle Length
Needle length selection depends on the depth the doctor wants
the acid to penetrate. If the usual epidermal thickness is 0.5 mm,
a 0.25 mm long needle will create wells inside the epidermis,
allowing the TCA to easily penetrate up to the basal layer. A
0.5 mm long needle device will perforate the full epidermal
thickness, bringing the acids up to the level of the Grenz zone.
Longer needles penetrate deeper into the skin, stimulate deeper
layers, and theoretically allow a deeper penetration of the acid.
We can nevertheless speculate that the depth of acid penetra-
tion will not exactly follow the length of the needles. In reality,
when TCA penetrates into the tiny wells, it induces a proteoco-
agulation of the walls of the well that will not allow a full pen-
etration up to the bottom of the hole. This treatment therefore
takes advantage of two types of stimulation: the one induced by
the needle itself, which is deeper, and the one induced by the
combination of the needle and the TCA.
The pressure on the needles will determine the depth of
the pixelization: very gentle pressure on a 3 mm long needle
will treat the skin more superficially than strong pressure on a
0.5 mm long needle.
Indications and Needle Length Selection
The main indication is skin anti-aging treatment, because the
needling associated with the peel will induce strong dermal
stimulation (Figure 38.4). The indication depends on the needle
length: a 0.25 mm needle is useful for treating epidermal prob-
lems, a 0.5 mm needle is used to treat problems that need action
at the level of the basal layer or Grenz zone, a 1 mm needle is
used to stimulate the papillary dermis, and longer needles for
stimulating the papillary and reticulary dermis.
Microneedling is a perforating treatment that can be
quite aggressive when needles are longer than 0.25 mm. The
device should be therefore sterile. The author strongly recom-
mends, for evident reasons, to use the microneedling device
only once and to discard it after use.
The face as well as the body can be treated. There is no
limitation on surface area as long as no potentially toxic prod-
uct is used after microneedling. A pixel peel is therefore an
interesting option for treating neck, arms, legs, and abdomen
skin laxity.
How to Do the Treatment
After careful skin disinfection, pass the microneedling device
over the skin four times in four different directions. The pres-
sure to be applied is similar to that used for scratching. The
roller has to be lifted from the skin at each pass to avoid passing
over the same holes four times, which would reduce the final
number of efficient punctures. The 0.25 and 0.5 mm needles
usually do not induce any bleeding (except when the 0.5 mm
needle is used on thin skin), but bleeding points occur when
longer needles are used. Bleeding is not a problem at all. The
use of the 0.25 mm needle is not painful for the patient, and the
0.5 mm is bearable. Longer needles could induce quite a lot of
pain, in direct relation to the length of the needles. The 2.5 mm is
more painful than to 1 mm needle. The microneedling treatment
fortunately allows an easy topical anesthesia: creating holes
through the stratum corneum allows an anesthetic solution to
easily pass to the basal layer of the epidermis and papillary der-
mis, where sensitive nervous terminations are found. When the
pixel peel technique is used, the author recommends passing
the roller on the skin superficially a few times to micro-perforate
the corneal layer and applying, directly on the micropunctured
area, a gauze soaked with a 2% adrenalinated lidocaine solu-
tion. Anesthesia occurs in parallel with vasoconstriction, which
stops eventual bleeding. Longer needles or deeper pressure can
then be applied without inducing local pain. At the same time,
the further application of TCA will not be painful as the skin is
under local anaesthesia (Figure 38.5).
Because the holes made by the needles have a tendency
to close quickly, thanks to skin’s elastic properties, the author
recommends treating the areas sequentially: the microneedling
device is passed on the first area (for example 50% of the
forehead) and the TCA peel is applied immediately after the
microneedling, when the holes are still open. The next area is
Figure 38.3  Microneedling roller. (Courtesy of Skin Tech, pat-
ented model.)
Figure 38.4  Local stamping for multiperforation of the skin at
the level of lentigines, before uniform application of Easy TCA. The
peel solution will penetrate deeper at the level of stamping.

382      Textbook of Chemical Peels
then treated the same way. The author usually uses the Easy
TCA peel (15% w/w) for this combined treatment. The number
of TCA coats depends on the visually appearance a few min-
utes after the acid application: the end point should be white
or gray-white frosting points at the level of every skin perfora-
tion. Then, the postpeel mask is applied. (The Easy TCA post-
peel mask has a strong anti-inflammatory efficacy, limiting side
effects; Figure 38.6.)
After the pixel peel and Easy TCA, a good esthetic result
is obtained for wrinkles, pigment, and irregular skin structure
(Figure 38.7).
How to Deepen the Peel
There are several ways to perform a deeper peel using the same
volume of Easy TCA solution: use longer needles, increase the
pressure on the perforating device (roll or stamp), or increase
the number of passes on the same area.
Obviously, a peel applied after five passes with strong
pressure on a 2 mm long needle device will be deeper than
the same peel applied after two passes of a 0.5 mm long needle
device. Note that a peel applied on a bloody area is partially
neutralized by the serum proteins.
The deepest technique induces a reticular dermis peel,
with a total social eviction of 8 days. Remember that in every
case, the deeper the peel, the higher the risk of side effects.
Postpeel Care
The postpeel care for a pixel peel done with short needles
(0.25 mm) is identical to that for a peel done without micronee-
dling. When microneedling is done using 1 mm to 2.5 mm nee-
dles, the postpeel skin shows a dark crusting at day 3 or 4, but
fast skin healing at the end of the first week.
If the pixel peel technique is used to reach the reticular
dermis, the skin should be covered with Yellskreen, which con-
tains bismuth subgallate powder, is a disinfectant, and speeds
up skin healing.
On day 3, sterile Vaseline should be applied on the edges
of the treated area, to avoid creating inflammation between the
crust and the skin surrounding it. On day 6, Vaseline should
be applied to the whole scab to unstick it and make it fall off
on day 7 without manipulation. The general postpeel recom-
mendations listed in the introduction of this chapter should be
respected.
Some results are shown in Figures 38.8 and 38.9.
Abrasive Techniques Associated with Easy TCA
Anterior chemabrasion is mainly used to treat acne scars and
stretch marks. Some doctors use it to treat deep wrinkle instead
of a deep phenol peel, to avoid toxicity and anesthesia prob-
lems. Easy TCA Pain Control is not intended to be used after
(a)
(b)
(c)
Figure 38.5  (a) Bleeding after skin pixelization using a 1.5 mm needle roller. (b) Gauze soaked in 2% adrenalinated lidocaine, for topical
anesthesia. (c) After actuation of adrenalinated lidocaine, anesthesia and bleeding stops.

Combination peels      383
abrasion because it contains phenol, which could trigger side
effects related to a faster and deeper phenol penetration and
assimilation (see Chapter 21).
Face-Lift Plus Peel
The high risk of focal or widespread facial necrosis contraindi-
cates a phenol peel immediately after a face-lift. If a face-lift and
a deep peel have to be combined, the surgical face-lift must be
done first and the chemical peel afterward to avoid the demar-
cation line being surgically lifted to the cheek. Caution usually
dictates a gap of 6 months between a surgical face-lift and a
deep peel. It is of course possible to perform a face-lift with-
out blepharoplasty and a phenol peel around the mouth and
eyelids at the same time of operation. There is no particular
risk of necrosis3 in these areas, as they have not been treated
surgically.
(a)
(b)
Figure 38.6  (a) Pinpoints of white-gray frosting appear at the level of the microperforations. (b) At the end of pixel peel, application of the
postpeel mask cream stops unnecessary inflammation.
(a)
(b)
Figure 38.7  Patient before (a) and after (b) pixel peel and Easy TCA.

384      Textbook of Chemical Peels
(a)
(b)
Figure 38.8  Patient before (a) and after (b) two sessions of pixel peel, with microneedling 5 mm needle and Easy TCA/postpeel mask.
(a)
(b)
Figure 38.9  Patient before (a) and after (b) three sessions of pixel peel, with microneedling 5 mm needle and Easy TCA/postpeel mask.

Combination peels      385
TCA, on the other hand, has been applied successfully
by different authors to the whole face at the end of a surgical
face-lift. The depth of peel determines the risk of necrosis. See
Figure 38.10.
Peeling Plus Botulinum Toxin
In some cases, botulinum toxin can be injected before a peel.
Speed of Absorption
Symptoms of botulism have been reported as soon as 2 hours
after ingestion of contaminated food, which means that intoxi-
cation is very rapid considering the time taken for digestion
and intestinal absorption. Uptake of the toxin by the synapse
is a rapid phenomenon that takes place in several stages, the
first of which is the binding of the toxin with an ectoreceptor/
acceptor. Next comes internalization in the presynaptic mem-
brane, the formation of endosomes, and the intracytoplasmic
interactions that eventually block the release of acetylcholine in
response to a nerve impulse.
The internalization and “internal actions” are slower and
more complex phenomena than simple binding at the recep-
tor/acceptor site. Vesicles that mediate internalization can be
seen after 30 minutes through an electron microscope. Uptake
of toxin at the receptor site is therefore very rapid and starts
within the first few minutes (or seconds?) after the toxin has
been injected into its immediate environment.
Different Depths of Action
Botulinum toxin (discovered in 1895 by Ermengem from
Belgium) is injected deep down in the facial muscles, whereas
peels do not injure the skin beyond the reticular dermis at
the most.
Influence of Inflammation
The inflammatory reaction and edema that follow TCA peels
(especially in simple aqueous solution) seem to be the deter-
mining risk factor of this combination. There is a risk of the
toxin traveling or diluting in the postpeel edema. Therefore,
under no circumstances should botulinum toxin be injected
after any peel whatsoever, as long as the inflammatory reaction
and edema are still active.
Injecting the Toxin before a Peel
It is generally accepted (but not officially specified) that
botulinum toxin should be injected at least 1 week before a
peel. The obvious advantage of this prior injection is that the
toxin blocks muscle movements and allows the dermis and
epidermis to regenerate on a “smooth base.” Eight days after
the toxin has been injected, its effect is complete and the peel
can be applied without any risk of the toxin being moved or
diluted.
However, this technique means an extra journey and
more lost time for the patient.
After 10 years of clinical experience in the simultaneous
use of botulinum toxin and Easy TCA, the author can safely
say that there is no risk in combining these two procedures
during the same session. The botulinum toxin is injected
first, and a rest period of 10 minutes is left to give time for the
uptake of the toxin at the presynaptic acceptor site. The Easy
TCA peel is then applied according to the basic protocol (see
Chapter 15). There has never been any change in duration or
depth of action, nor has the toxin moved during this combined
procedure.
To the author’s knowledge, injection of botulinum toxin
immediately before other peels has not been tested, and it is
advisable to leave a rest period of 1 week after injection of the
toxin if a peel other than Easy TCA is applied.
Trichloroacetic Acid and Fillers
Hyaluronates and papillary peels clash on the battlefield of the
dermis, and it is generally recommended not to inject sensi-
tive polymers before applying a peel. Hyaluronic acid is a large
carbohydrate polymer that is sensitive to external aggressions
such as free-radical attacks. Peels that produce a severe inflam-
matory reaction generate a large number of free radicals that
can break the hyaluronate polymers, shorten their lifespan in
the dermis, and introduce a great many macrophage cells into
the dermis that can phagocytose the hyaluronates.
Under these conditions, the lifespan of the hyaluronic
acid is shortened, and filler injections with sensitive polymers
should be given some time after a peel. This technique also
means an extra journey and more lost time for the patient. The
author therefore has used Easy TCA at the same time as injec-
tions of collagen and different reticulated hyaluronic acids
(Restylane, Juvederm, Esthélis, etc.) and has not seen any
difference in the behavior of wrinkles, whether or not these
injections are combined with Easy TCA. The filler injection
is given first and Easy TCA (solution plus postpeel mask) is
applied immediately afterward. The antioxidant qualities of
the postpeel mask seem to explain the fact that there is no
interaction.
Figure 38.10  A phenol peel (Lip & Eyelid Formula) has been
applied on the lower eyelids and around the mouth, immediately
after a surgical face-lift. A medium-depth TCA peel (Unideep) also
has been applied on the face after the face-lift. Phenol cannot
be applied on areas where the surgical face-lift undermined the
skin; the risk of full thickness skin necrosis would be very high.
(Courtesy of Dr. Espinosa, Mexico.)

386      Textbook of Chemical Peels
Microdermabrasion with Corundum Crystals
In reality, the advantage of preceding a peel with microderm-
abrasion is far from clear, as microdermabrasion does not pro-
vide abrasion as even as that produced by simple sandpaper.
The handpiece of the microdermabrasion unit is comparable to
a pencil, and its action can be likened to drawing a criss-cross
of lines with clear spaces in between. The TCA solution pen-
etrates more deeply in the base of the abrasion lines, giving a
linear and uneven peel (Figure 38.11).
NOTES
1. Here, 3–5 seconds means in practice 3 seconds on thin skin and
5 seconds on thick skin.
2. Or around the edges of scars to attenuate the difference in height.
3. Asken S. Unoccluded Baker–Gordon phenol peels—Review and
update. Journal of Dermatologic and Surgical Oncology. 1989; 15:
998–1008.
(a)
(b)
Figure 38.11  (a) Schematic diagram of application pattern: red points are zones of double abrasion = deeper penetration. (b) When
microdermabrasion is done in circles, the circles cross each other many times, creating points of double, triple, and quadruple abrasion,
resulting in deeper penetration at these points.

MEDICINE / DERMATOLOGY TEXTBOOK OF CHEMICAL PEELS Superficial, Medium, and Deep Peels in Cosmetic Practice SECOND EDITION Chemical peels have returned to the forefront of the practitioner's armamentarium and are popular because they offer nearly immediate results. The Textbook of Chemical Peels is the definitive guide to all types of chemical peel treatments. It covers the practical application and scientific background for a wide variety of chemical peels. The book reflects the new classification of peels as a medical, rather than cosmetic, treatment and helps providers by making chemical peel formulas easier, safer, and quicker to use. The book covers the appropriate selection of peels to treat the face, scalp, neck, hands, body, and forearms. It also discusses the use of peels to treat aging skin, stretch marks, scars, melasma, chloasma, acne, postinflammatory hyperpigmentation, and scalp keratoses. The mechanism of action, indication, application, and results are discussed for a variety of chemical peels including alpha hydroxy acids, trichloroacetic acid, salicylic acid, resorcine, and phenols. Also covered are any contraindications, precautions, and safety issues. This edition includes new material on adjunctive procedures such as microneedling and mesotherapy as well as new information on mosaic peels. Treatment prior to and following the peel are also discussed in detail, and a full chapter is devoted to discussing complications associated with chemical peels. The book incorporates color clinical photographs throughout as well as descriptive tables summarizing key information. Based on the author's extensive experience in both research and practice, this updated reference is an invaluable guide to all health professionals involved with chemical peel treatments. WITH VITALSOURCE® EBOOK • download the ebook to your computer or access it anywhere with an internet browser • search the full text and add your own notes and highlights • link through from references to PubMed K22350 ISBN: 978-1-4822-2393-4 90000 CRC CRC Press Taylor & Francis Group an informa business 6000 Broken Sound Parkway, NW Suite 300, Boca Raton, FL 33487 711 Third Avenue New York, NY 10017 2 Park Square, Milton Park Abingdon, Oxon OX14 4RN, UK 9 781482 223934