Salicylic Acid Peels

Salicylic acid (SA) is a beta-hydroxy acid. Salicylic acid is a naturally occurring substance found in the bark of the willow tree. Salicylic acid peels range in concentration from 20–30%, and peels are performed every 3–4 weeks for a total of three to five treatments. Sal icylic acid peels are indicated in the treatment of acne vulgaris, melasma, postinflammatory hyperpigmentation (Figs. 4.1, 4.2, 4.3, 4.4), rough/oily skin with enlarged pores, and mild to moderate photodamaged skin (Table 4.2). Salicylic acid peels are safe and efficacious in skin types I–VI [14].

Salicylic acid has been formulated in a hydroethanolic vehicle at concentrations of 20% and 30% for use as a superficial peeling agent [33]. It is a lipophilic agent,which produces desquamation of the upper lipophilic layers of the stratum corneum [14]. Its efficacy for the treatment of acne and photoaging has been well documented in the Fitzpatrick skin types I–III [33, 10] as well as in patients with Fitzpatrick skin types V and VI [14]. Salicylic acid peels are the preferred therapy for comedonal acne as it is lipophilic and concentrates in the pilosebaceous apparatus. It is effective as adjunctive treatment for open and closed comedones and at resolving postacne erythema and hyperpigmentation [34].

Because it is a lipid-soluble comedolytic, salicylic acid acts by decreasing corneocyte cohesion at the follicular opening and assists in comedone plug extrusion [35, 36]. In addition, the salicylic acid peel can be combined with hydroquinone 4% (pre- and postprocedure) to expedite the clearing of hyperpigmented lesions and significantly decrease the occurrence of postpeel hyperpigmentation seen more commonly in skin types V and VI [14].

As with all superficial peeling agents, prior to applying the wounding agent, the face is cleansed with alcohol- or acetone-soaked sponges. Then the salicylic acid agent (20% or 30% in a hydroethanolic solution) is applied to the face.Patients experience stinging and burning with an intensity that is greater than that of 70% glycolic acid, but this ceases rapidly. The SA peel causes a superficial anesthesia so patients can be reassured that the stinging and burning will cease within a couple of minutes [10].

The agent should be applied to cosmetic units of the face in any order.Uniformity of application is easily observed as a white precipitate of salicylic acid is seen in the areas where the agent has been applied. The agent is applied to the face for 3–4 min. Then the face is washed with water or a mild cleanser. Of note, once the hydroethanolic vehicle has volatilized leaving a white precipitate of salicylic acid on the surface of the skin, there is very little penetration of the active agent. Thus, there is no concern regarding timing or overpeeling.

The majority of patients tolerate this procedure without side effects. Side effects,which are seen, include transient dryness and hyperpigmentation, which resolve within 1–2 weeks; and temporary superficial crusting (Fig. 4.5) and edema, which clear in about 7 days.

Salicylism has not been seen as a side effect postpeel since the total amount of SA applied is very small and the majority of the solution is removed once the solution has volatized. In addition,Kligman tested serum levels of subjects after peeling, and the concentrations were far below levels of salicylate toxicity and were below anti-inflammatory levels [10]. Of note,more peeling is seen in areas of prepeel inflammation, e.g., inflammatory acne or seborrheic dermatitis. Peeling usually begins 2 days postpeel and can extend for up to 7 days postpeel. This agent causes significantly more desquamation than glycolic acid peels [10]. The efficacy of salicylic acid peels is directly correlated to the degree of desquamation that is seen postpeel. Postprocedure regimen should include the use of sunscreen, avoidance of excessive sun exposure, and the daily application of a moisturizer.