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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Adverse effects of treatment with adapalene, including erythema, scaling, dryness, pruritis and burning, occur mainly during the first month of use, decreasing thereafter. Nevertheless, in comparative trials, adapalene has demonstrated a superior tolerability profile to other retinoids.

A meta-analysis of five large randomized trials comprising 900 patients demonstrated equivalent acne reduction, quicker onset of action, significant at one week, and fewer side effects with 0.1% adapalene gel compared with 0.025% tretinoin gel.¹³ The tolerability profile of adapalene also was significantly better regarding scaling, erythema, dryness, immediate and persistent burning and immediate pruritis.¹³

In two three-week trials, 0.1% adapalene gel demonstrated better tolerability and less irritation than 0.1% tretinoin cream, 0.05% tretinoin cream, 0.025% tretinoin cream, 0.01% tretinoin gel, 0.025% tretinoin gel and 0.1% tretinoin gel microspheres. In both studies, 0.1% adapalene gel was no more irritating than the petrolatum control.¹⁴

A recent study comparing a combination gel containing 0.1% adapalene and 2.5% BPO to a vehicle and individual monotherapies demonstrated combination therapy to have a faster onset of action, significantly greater lesion reduction and no increase in adverse events, compared with monotherapy.¹⁵

Azelaic Acid

Azelaic acid, a naturally occurring, saturated C9-dicarboxylic acid, modifies epidermal keratinization, i.e. cytostatic; combats both aerobic and anaerobic bacteria, reducing P. acnes proliferation; and exhibits anti-inflammatory activity. Azelaic acid affects differentiation of human keratinocytes by decreasing synthesis of the keratin filament aggregating protein filaggrin.