Keratolytic Treatments for Acne: A Review

By: Ali Alikhan, MD, Mayo Clinic; and Howard I Maibach, MD, University of California School of Medicine

Posted: September 29, 2010, from the October 2010 issue of Cosmetics & Toiletries.

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In combination with 3% erythro-mycin/5% BPO, 20% azelaic acid produced a marked and relatively expedient decrease in inflammatory lesions. At the end of 12 weeks, reduction in this group was similar to 20% azelaic acid/1% clindamycin, which was the most tolerable of all regimens. In non-inflammatory lesion treatment, however, azelaic acid with 4% BPO and azelaic acid with 0.025% tretinoin were most effective. The azelaic acid plus benzoyl peroxide regimen also achieved the highest patient ratings in overall therapeutic result.¹⁸

Salicylic Acid

A core component of many OTC acne treatments, salicylic acid (SA) is a widely available topical keratolytic agent. It has a profound structural effect on the SC, resulting in disruption of intercorneocyte cohesion and subsequent desquamation. Dissolution of intercellular cement is further supported by a novel tape stripping/colorimetric protein assay to evaluate keratolytic efficacy.²¹

Although local skin irritation, e.g. peeling, at concentrations greater than 2% is common, systemic toxicity is rare. If applied to large areas for prolonged periods of time, salicylate toxicity, toxic inner ear damage and hypersensitivity reactions are plausible.

Two 12-week studies comparing 0.5% and 2% SA pads with placebo pads demonstrated significant efficacy in reducing inflammatory acne, non-inflammatory acne and total lesions, while producing significantly higher proportions of good to excellent overall treatment assessments. In one study, 60% of individuals using 2% and 0.5% SA pads experienced a 75–100% decrease in total lesion count, compared with 2% of patients receiving a placebo.²² In both studies, side effects were minimal and included peeling, itching, burning and redness.

A 12-week study found 2% SA cream superior to 5% BPO cream in reducing closed comedones, open comedones, inflammatory lesions and total lesions.²² A four-week crossover study comparing a 2% SA acne cleanser with a 10% BPO wash demonstrated that only patients treated with the SA cleanser had a significant decrease in comedonal lesions.²³ Stated differently, both groups demonstrated significant improvement in comedonal count when treated with SA, whereas BPO treatment either worsened or insignificantly improved comedonal quantity.²³

Glycolic Acid