Chapter 6 Salicylic Acid
Chapter 6 Salicylic Acid in this chapter. 6 Contents 6.1
History . . . . . . . .
. . . . . . . . . 49 6.2
Chemical Background/Properties . . . 49 6.3 Formulations
. . . . . . . . .
. . . . . 50 6.4 Indications . .
. . . . . . . . . .
. . . 50 6.5 Contraindications . . .
. . . . . . . . 50 6.6 Patient
Preparation . . . . . . .
. . . . 51 6.7 Peeling Technique . .
. . . . . . . . . 51 6.8
Post-peeling Care and Complications . 55 6.9 Advantages .
. . . . . . . . . .
. . . . 55 6.10 Disadvantages . . .
. . . . . . . . . . 56
6.11 Side Effects . . . . . .
. . . . . . . . . 56 6.12
Patient’s Informed Consent . . . . . . 56
References . . . . . . .
. . . . . . . . 57 6.1 History P.G.
Unna, a German dermatologist, was the first to describe the properties and use
of salicylic acid. It has since been used for many decades as a keratolytic
agent in concentrations of 3 to 6%. Salicylic acid is frequently utilized in
topical acne preparations because of its comedolytic effects. In addition, it
facilitates the penetration of other topical agents. 6.2 Chemical
Background/Properties Salicylic acid (ortho-hydroxybenzoic acid) is a beta
hydroxy acid agent (Fig. 6.1). It is a lipophilic compound which removes
intercellular lipids that are covalently linked to the cornified envelope
surrounding cornified epithelioid cells [1]. Due to its antihyperplastic
effects on the epidermis, multiple investigators have used salicylic acid as a
peeling agent [2, 3, 4]. Recently, histologic assessments using salicylic acid
peels in hairless mice reported loss of cornified cells followed by activation
of epidermal basal cells and underlying fibroblasts. These findings suggest
that salicylic acid peeling can alter the underlying dermal tissue without
directly wounding the tissue or causing inflammation [5]. Salicylic acid has
also been shown to have anti-inflammatory and antimicrobial properties. When
used in combination with benzoic acid in Whitfield’s ointment, it has
fungicidal properties. Fig. 6.1. Chemical structure 6.3 Formulations A variety
of formulations of salicylic acid have been used as peeling agents. These
include 50% ointment formulations (Table 6.1) [2, 3], as well as 10, 20 and 30%
ethanol formulations (Table 6.2) [4, 6]. More recently, commercial formulations
of salicylic acid have become available (BioGlan Pharmaceuticals Company,
Malvern, PA; Bionet Esthetics, Little Rock, AR). 6.4 Indications The efficacy
of salicylic acid peeling has been assessed in several studies. Fifty percent
salicylic acid ointment peeling was first used by Aronsohn to treat 81 patients
who had freckles, pigmentation, and aging changes of the hands [3]. He reported
excellent results. Subsequently, Swinehart [7] successfully used a
methyl-salicylate buffered, croton oil-containing, 50% salicylic acid ointment
paste for treatment of lentigines, pigmented keratoses and actinically damaged
skin of the dorsal hands and forearms. After pretreatment with topical
tretinoin and localized TCA 20%, the 50% salicylic acid paste was applied to
the affected area and occluded for 48 h. Following dressing removal, peeling
and desquamation occurred and was relatively complete by the tenth day. Overall
results were described as excellent. Despite these results, salicylic acid
peeling did not move into the arena of popular peeling techniques until the mid
1990s. Kligman and Kligman [4] ushered salicylic acid into the current arena of
superficial peeling agents. They treated 50 women with mild to moderate
photodamage, reporting improvement in pigmented lesions, surface roughness and
reduction in fine lines. Grimes et al. [8] reported substantial efficacy and
minimal side effects in 25 patients treated with 20 and 30% salicylic acid
peels in darker racial-ethnic groups. Conditions treated included acne
vulgaris, melasma and post-inflammatory hyperpigmentation. Thirty-five Korean
patients with facial acne were treated biweekly for 12 weeks with 30% salicylic
acid peels [9]. Both inflammatory and non-inflammatory lesions were
significantly improved. In general, the peel was well tolerated with few side
effects. Given these findings, indications for salicylic acid peels include
acne vulgaris (inflammatory and non-inflammatory lesions), acne rosacea,
melasma, post-inflammatory hyperpigmentation, freckles, lentigines, mild to
moderate photodamage, and texturally rough skin. 6.5 Contraindications In
general, there are few contraindications to salicylic acid chemical peeling.
Salicylic acid peels are well tolerated in all skin types (Fitzpatrick’s I–VI)
and all racial/ethnic groups. General contraindications include salicylate
hypersensitivity/allergy; unrealistic patient expectations; active
inflammation/dermatitis or infection at the salicylic acid peeling site; acute
viral infection; pregnancy; and isotretinoin therapy within 3–6 months of the
peeling procedure. The author has performed more than 1,000 salicylic acid
peels without observing any 50 Pearl E. Grimes 6 Table 6.1 Formulations of
salicylic acid: salicylic acid ointment Salicylic acid powder USP 50% Methyl
salicylate 16 drops Aquaphor 112 g From Swinehart [7] Table 6.2 Formulations of
salicylic acid: salicylic acid solutions Salicylic acid Weight of Amount of
peel % salicylic acid ethyl alcohol powder (g) 95% (cc) 10 10 100 20 20 100 30
30 100 40 40 100 50 50 100 From Draelos [6] evidence of salicylate
allergy/hypersensitivity following a salicylic acid peel. 6.6 Patient
Preparation Peel preparation varies with the condition being treated. Regimens
differ for photodamage, hyperpigmentation (melasma and post-inflammatory
hyperpigmentation) and acne vulgaris [10]. In addition there are special issues
to be considered when treating darker racial-ethnic groups (see darker skin
section). A detailed history and cutaneous examination is performed in all
patients prior to chemical peeling. Standardized photographs are taken of the
areas to be peeled including full-face frontal and lateral views. Use of
topical retinoids (tretinoin, tazarotene, retinol formulations) for 2–6 weeks
prior to peeling thin the stratum corneum and enhance epidermal turnover. Such
agents also reduce the content of epidermal melanin and expedite epidermal
healing. Retinoids also enhance the penetration of the peeling agent. They
should be discontinued several days prior to the peeling procedure. Retinoids
can be resumed post-operatively after all evidence of peeling and irritation
subsides. In contrast to photodamage, when treating conditions such as melasma,
post-inflammatory hyperpigmentation, and acne as well as darker skin types,
retinoids should be discontinued 1 or 2 weeks before peeling or even eliminated
from the prep to avoid post-peel complications such as excessive erythema,
desquamation, and post-inflammatory hyperpigmentation. Topical alpha hydroxy
acid or polyhydroxy acid formulations can also be used to prep the skin. In
general, they are less aggressive agents in impacting peel outcomes. The skin
is usually prepped for 2–4 weeks with a formulation of hydroquinone 4% or
higher compounded formulations (5–10%) to reduce epidermal melanin. This is
extremely important when treating hyperpigmentation. Although less effective,
other topical bleaching agents include azelaic acid, kojic acid, arbutin, and
licorice (see photoaging section). Patients can also resume use of topical
bleaching agents post-operatively after peeling and irritation subsides. When
treating acne vulgaris, topical and systemic therapies (if indicated) are
initiated 2 to 4 weeks prior to peeling. Topical antibiotics and benzoyl
peroxide based products can be used daily and discontinued 1 or 2 days prior to
peeling. However, unless a deeper peel is desired, retinoids should be
discontinued 7–10 days prior to salicylic acid peeling. Broad-spectrum
sunscreens (UVA and UVB) should be worn daily (see Photodamage, Sunscreen
section). 6.7 Peeling Technique Despite some general predictable outcomes, even
superficial chemical peeling procedures can cause hyperpigmentation and
undesired results. Popular standard salicylic acid peeling Salicylic Acid
Chapter 6 51 Fig. 6.2. Salicylic acid precipitate techniques involve the use of
20 and 30% salicylic acid in an ethanol formulation. Salicylic acid peels are
performed at 2- to 4-week intervals. Maximal results are achieved with a series
of three to six peels. The author always performs the initial peel with a 20%
concentration to assess the patients’ sensitivity and reactivity. Before
treatment, the face is thoroughly cleansed with alcohol and/or acetone to
remove oils. The peel is then applied 52 Pearl E. Grimes 6 Fig. 6.3. a Frosting
after salicylic acid. b Crusting 48 h later. c Resolution of crusting in 3 to 4
days a b c with 2×2 wedge sponges, 2×2 gauze sponges, or cotton-tipped
applicators. Cotton-tipped swabs can also be used to apply the peeling agent to
periorbital areas.A total of two to three coats of salicylic acid is usually
applied. The acid is first applied to the medial cheeks working laterally,
followed by application to the perioral area, chin, and forehead. The peel is
left on for 3–5 min. Most patients experience some mild burning and stinging
during the procedure. After 1–3 min, some patients experience mild peel-related
anesthesia of the face. Portable handheld fans substantially mitigate the
sensation of burning and stinging. A white precipitate, representing
crystallization of the salicylic acid, begins to form at 30 s to 1 min
following peel application (Fig. 6.2). This should not be confused with
frosting or whitening of the skin, which represents protein agglutination.
Frosting usually indicates that the patient will observe some crusting and
peeling following the procedure (Fig. 6.3a–d). This may be appropriate when
treating photodamage. However, the author prefers to have minimal to no
frosting when treating other conditions. After 3–5 min the face is thoroughly
rinsed with tap water, and a bland cleanser such as Cetaphil is used to remove
any residual salicylic acid precipitate. A bland moisturizer is applied after
rinsing. My favorites are Cetaphil, Purpose, Theraplex, and SBR Lipocream
(Figs. 6.4a, b, 6.5a, b and 6.6a, b). Salicylic Acid Chapter 6 53 Fig. 6.3. d
Complete clearing of hypopigmentation by days 7–10. Note improvement in acne
Fig. 6.4a. Melasma before and after a series of five salicylic acid peels and
4% hydroquinone d a 54 Pearl E. Grimes 6 Fig. 6.4b. Melasma before and after a
series of five salicylic acid peels and 4% hydroquinone Fig. 6.5a, b. Acne
vulgaris before and after four salicylic acid peels b a b 6.8 Post-peeling Care
and Complications Bland cleansers and moisturizers are continued for 48 h or
until all post-peel irritation subsides. Patients are then able to resume the
use of their topical skin care regimen including topical bleaching agents, acne
medications, and/or retinoids. Post-peel adverse reactions such as excessive
desquamation and irritation are treated with low to high potency topical
steroids. Topical steroids are extremely effective in resolving post-peel
inflammation and mitigating the complication of post-inflammatory
hyperpigmentation. In the author’s experience, any residual post-inflammatory
hyperpigmentation resolves with use of topical hydroquinone formulations following
salicylic acid peeling. 6.9 Advantages The key benefits of salicylic acid
peeling include: An established safety
profile in patients with skin types I–VI
An excellent peeling agent in patients with acne vulgaris Given the appearance of the white precipitate,
uniformity of application is easily achieved
After several minutes the peel can induce an anesthetic effect whereby
increasing patient tolerance Salicylic Acid Chapter 6 55 Fig. 6.6a, b. Acne
rosacea before and after three salicylic acid peels, moderate improvement a b
6.10 Disadvantages Limited depth of
peeling Minimal efficacy in patients
with significant photodamage 6.11 Side Effects Side effects of salicylic acid
peeling are mild and transient. In a series of 35 Korean patients, 8.8% had prolonged
erythema that lasted more than 2 days [9]. Dryness occurred in 32.3%,
responding to frequent applications of moisturizers. Intense exfoliation
occurred in 17.6%, clearing in 7–10 days. Crusting was noted in 11.7%. There
were no cases of persistent post-inflammatory hyperpigmentation or scarring. In
a series of 25 patients comprising 20 African Americans and five Hispanics, 16%
experienced mild side effects [8]. One patient experienced temporary crusting
and hypopigmentation that cleared in 7 days. Three patients had transient
dryness and hyperpigmentation that resolved in 7–14 days. Salicylism, or
salicylic acid toxicity, is characterized by rapid breathing, tinnitus, hearing
loss, dizziness, abdominal cramps, and central nervous system reactions. It has
been reported with 20% salicylic acid applied to 50% of the body surface, and
it has also been reported with use of 40 and 50% salicylic acid paste
preparations [7]. The author has peeled more than 1,000 patients with the
current 20 and 30% marketed ethanol formulations and has observed no cases of
salicylism. 6.12 Patient’s Informed Consent I, ________________, hereby consent
to having my _____________ (site) treated with SALICYLIC ACID CHEMICAL PEELING.
The peel will be performed to improve the overall appearance of the skin at the
site of treatment. Salicylic acid peels are used to improve acne vulgaris,
hyperpigmentation (dark spots), rough texture, oily skin, and photodamage (sun
damage). The procedure involves first having the peel site prepped with
alcohol, acetone or other pre-peel cleansing agents. The peeling agent is
applied for 3–5 min followed by cleaning with tap water and a bland cleanser.
In general, salicylic acid peels are extremely well tolerated. However, the
procedure can cause swelling, redness, crusting, dryness and obvious peeling of
the face which could last for up to 7–10 days. I understand that there is a
small risk of developing permanent darkening after the procedure.There is a
rare chance that the peel could cause undesirable pigment loss at the treated
site, the condition being treated could worsen after the peeling procedure, or
a scar could develop.In addition,there is a small chance that a bacterial
infection could develop, or the peel could also trigger a flare of a pre-existing
Herpes infection at the treated site. In addition, there have been uncommon
cases of allergic reactions to salicylates (the active peel ingredient).The
benefits and side effects of the procedure have been explained to me in
detail.All of my questions have been answered.
I am in stable health. I have not
used Isotretinoin in the past 6 months.
I have no allergies to salicylic acid.
I am not pregnant. Outcomes are not guaranteed. Signature of Patient
Date Patient Name (Please Print) Witness Date 56 Pearl E. Grimes 6 References
1. Lazo ND, Meine JG, Downing DT (1995) Lipids are covalently attached to rigid
corneocyte protein envelope existing predominantly as beta-sheets: a solid
state nuclear magnetic resonance study. J Invest Dermatol 105 : 296–300 2.
Swinehart JM (1992) Salicylic acid ointment peeling of the hands and forearms.
J Dermatol Surg Oncol 18 : 495–498 3. Aronsohn RB (1984) Hand chemosurgery. Am
J Cosmet Surg 24–28 4. Kligman D, Kligman AM (1998) Salicylic acid peels for
the treatment of photoaging. Dermatol Surg 24 : 325–328 5. Imayama S, Ueda S,
Isoda M (2000) Histologic changes in the skin of hairless mice following
peeling with salicylic acid. Arch Dermatol 136 : 1390– 1395 6. Draelos ZD
(2000) Atlas of cosmetic dermatology. Churchill Livingstone, New York, pp 94–97
7. Swinehart JM (1992) Salicylic acid ointment peeling of the hands and
forearms. Effective nonsurgical removal of pigmented lesions and actinic
damage. J Dermatol Surg Oncol 18 : 495–498 8. Grimes PE (1999) The safety and
efficacy of salicylic acid chemical peels in darker racial-ethnic groups.
Dermatol Surg 18–22 9. Lee HS, Kim IH (2003) Salicylic acid peels for the
treatment of acne vulgaris in Asian patients. Dermatol Surg 29 : 1196–1199 10.
Brody HJ (1997) Chemical peeling, 2nd ed. Mosby, St Louis Salicylic Acid
Chapter 6 57
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