Salicylic Acid Peels

Published on 15/03/2015 by admin

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5 Salicylic Acid Peels

Pearl E. Grimes

Introduction

Salicylic acid (ortho-hydroxybenzoic acid) is a beta hydroxy acid agent (Fig 5.1), the properties and use of which were first described by Unna, a German dermatologist. It is a lipophilic compound which removes intercellular lipids that are covalently linked to the cornified envelope surrounding cornified epithelioid cells. Owing to its antihyperplastic effects on the epidermis, multiple studies document the beneficial effects of salicylic acid as a peeling agent. Salicylic acid has also been shown to have anti-inflammatory and antimicrobial properties. See Table 5.1.

Figure 5.1 Chemical structure of salicylic acid

Table 5.1 Differences between AHAs and BHAs

	AHA	BHA
Lipophilic	−	+
Anesthetic properties	−	+
Must be neutralized	+	−
Frosts	−	+
Useful in pregnancy and nursing	+	−
Safe in all skin types	+	+

Patient Selection

Indications for salicylic acid peels include acne vulgaris (inflammatory and noninflammatory lesions), acne rosacea, melasma, postinflammatory hyperpigmentation (PIH), freckles, lentigines, mild to moderate photodamage, and texturally rough skin (Figs 5.2–5.4). Salicylic acid peels are well tolerated in all skin types (Fitzpatrick’s I to VI) and in all racial/ethnic groups. See Box 5.1.

Figure 5.2 Patient with texturally rough skin before (A) and after (B) a series of five salicylic acid peels

Figure 5.3 Patient with moderate melasma before (A) and after (B) a series of three salicylic acid peels and 4% hydroquinone

Figure 5.4 Patient with nodulocystic acne before (A) and after (B) a series of five salicylic acid peels

Box 5.1

Salicylic acid indications

• Acne (inflammatory and noninflammatory)

• Rosacea

• Melasma

• PIH

• Freckles, lentigines

• Mild/moderate photodamage

• Rough texture

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. He reported excellent results. Subsequently, other practitioners successfully used a 50% salicylic acid ointment paste, containing croton oil and buffered with methyl salicylate, 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 hours. 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 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 and surface roughness, and reduction in fine lines.

Grimes and colleagues 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 PIH. In addition, in a retrospective analysis of 90 patients treated by the author with salicylic acid peeling, 70% had significant improvement in acne and pigmentation, 25% had mild improvement, and 5% had minimal improvement.

Lee and colleagues treated 35 Korean patients with facial acne using 30% salicylic acid peels biweekly for 12 weeks. Both inflammatory and noninflammatory lesions were significantly improved. In general, the peel was well tolerated with few side effects. Given the aforementioned findings, there are several advantages and disadvantages of salicylic acid peeling (Table 5.2).

Table 5.2 Advantages and disadvantages of salicylic acid peeling

Advantages	Disadvantages
An established safety profile in patients with skin types I–VI	Limited depth of peeling
It is an excellent peeling agent in patients with acne vulgaris	Minimal efficacy in patients with significant photodamage
Given the appearance of the white precipitate, uniformity of application is easily achieved
After several minutes the peel can induce an anesthetic effect, thereby increasing patient tolerance

• Contraindications and exclusions

In general, there are few contraindications to salicylic acid chemical peeling. General contraindications include salicylate hypersensitivity or allergy; unrealistic patient expectations; active inflammation/ dermatitis or infection at the salicylic acid peeling site; acute viral infection; pregnancy; and isotretinoin therapy within 3 to 6 months of the peeling procedure.

Overview of Treatment Strategy

• Patient preparation

Salicylic acid peel preparation varies with the condition being treated. Regimens differ for photodamage, hyperpigmentation (melasma and PIH) and acne vulgaris. In addition there are special issues to be considered when treating darker racial/ethnic groups. A detailed history and cutaneous examination should be 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 to 6 weeks prior to peeling thins the stratum corneum and enhances epidermal turnover. Such agents also reduce the content of epidermal melanin and expedite epidermal healing. Retinoids also enhance the penetration and depth of chemical peeling. Optimal effects are demonstrated with these agents when treating photodamage in Fitzpatrick skin types I–III. They can be utilized until 1 or 2 days prior to peeling. Retinoids can be resumed postoperatively after all evidence of peeling and desquamation subsides.

In contrast to photodamage, when treating conditions such as melasma and PIH, retinoids should either be discontinued 1 or 2 weeks before peeling or completely eliminated from the peeling preparation to avoid postpeel complications such as excessive erythema, desquamation, and PIH. These conditions are more common in darker racial/ethnic groups, populations at greater risk for postpeel complications. Similar precautions should be taken in acne patients with darker skin types (V and VI).

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 to 4 weeks with a formulation of hydroquinone 4% or higher compounded formulations (5–10%) to reduce epidermal melanin. This is extremely important when treating the aforementioned dyschromias. Although less effective, other topical bleaching agents include azelaic acid, kojic acid, arbutin, and licorice. Patients can also resume use of topical bleaching agents postoperatively after peeling and irritation subsides. Broad-spectrum sunscreens (UVA and UVB) should be worn daily. See Table 5.3.

Table 5.3 Skin regimen: preparation

	Start	Stop
Retinoids	2–6 weeks before	2 days before in photoaging 1–2 weeks before in PIH, melasma and in darker skin types
AHAs/PHAs	2–6 weeks before	2 days before in photoaging 1–2 weeks before in PIH, melasma and in darker skin types
HQ (4–10%)	2–4 weeks before peel

• Peel formulations

A variety of formulations of salicylic acid have been used as peeling agents. These include 50% ointment formulations (Table 5.4) as well as 20% and 30% ethanol formulations. More recently, commercial formulations of salicylic acid have become available (BioGlan Pharmaceuticals Co., Malvern, PA; Bionet Esthetics, Little Rock, AR).

Table 5.4 Formulations of salicylic acid ¹

Salicylic acid ointment	Salicylic acid solutions
Salicylic acid powder USP 50%	Salicylic acid 20%
Methyl salicylate, 16 drops	Salicylic acid 30%
Aquaphor 112 g

¹ Manufacturers: BioGlan Pharmaceuticals; Bionet Esthetics

From: Swinehart 1992

• Peeling technique

Despite some generally predictable outcomes, even superficial chemical peeling procedures can cause hyperpigmentation and undesired results. Popular standard salicylic acid peeling 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 (see Figs 5.2–5.4, Figs 5.5, 5.6).

Figure 5.5 Patient with acne before (A) and after (B) a series of salicylic acid peels

Figure 5.6 Patient with pseudofolliculitis barbae and postinflammatory hyperpigmentation before (A) and after (B) a series of five salicylic acid chemical peels.

The author always performs the initial peel with a 20% concentration to assess the patient’s sensitivity and reactivity. Before treatment, the face is thoroughly cleansed with alcohol and/or acetone to remove oils (Box 5.2). The peel is then applied with 2″ × 2″ (5 cm²) wedge sponges, 2″ × 2″ gauge sponges, or cotton tipped applicators. Cotton tipped swabs can also be used to apply the peeling agent to periorbital areas (Fig. 5.7). A total of two to three coats of salicylic acid is usually applied. Three coats are most often used in patients with photodamage. 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 to 5 minutes (Fig. 5.8). Most patients experience some mild burning and stinging during the procedure. After 1 to 3 minutes, some patients experience mild peel-related anesthesia of the face. Portable hand held fans substantially mitigate the sensation of burning and stinging.

Figure 5.7 Chemical peel tray setup

Figure 5.8 Progression of peel. (A) Baseline prior to application of peel; (B) 1 min after peel application; (C) 2 min after peel application (note more intense frosting representing complete crystallization of salicylic acid); (D) complete frosting achieved 4 min after peel application, and (E) postpeel after salicylic acid precipitate removed

A white precipitate, representing crystallization of the salicylic acid, begins to form at 30 seconds to 1 minute following peel application (Fig. 5.8). 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. This may be appropriate when treating photodamage. However, the author prefers to have minimal to no frosting when treating other conditions. After 3 to 5 minutes the face is thoroughly rinsed with tap water, and a bland, soapless cleanser such as Cetaphil is used to remove any residual salicylic acid precipitate. A similarly bland moisturizer is applied after rinsing. (My favorites are Cetaphil, Purpose, Theraplex, and SBR Lipocream.) Bland cleansers and moisturizers are continued for 48 hours or until all postpeel irritation and desquamation subsides. Patients are then able to resume the use of their topical skin care regimen including topical bleaching agents, acne medications, and/or retinoids.

Postpeeling Complications and Side Effects

Postpeel complications can include excessive crusting, desquamation, erythema/inflammation, and dyschromia (Fig. 5.9). Excessive desquamation and irritation are treated with low to high potency topical steroids. Topical steroids are extremely effective in resolving postpeel inflammation and mitigating the complication of PIH. In the author’s experience, any residual PIH resolves with use of topical hydroquinone formulations following salicylic acid peeling.