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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Cyanoacrylate skin surface biopsies have demonstrated significant reductions (> 50%) in comedo count after four months of twice-daily 20% azelaic acid treatment, when compared with the vehicle alone. Additionally, comedone reduction was similar in magnitude to that of 0.05% retinoic acid cream.¹⁶

A 12-week controlled study comparing 20% azelaic acid treatment, its maximum usage in prescription treatments, with a vehicle demonstrated that azelaic acid significantly improved mild to moderate acne. Azelaic acid treatment decreased inflammatory lesions by 72% and comedones by 55.6%. In addition, 64% of individuals treated with azelaic acid reported good to excellent improvement.¹⁷

Azelaic acid has demonstrated inflammatory and non-inflammatory acne reduction in numerous studies, even when compared with tretinoin, benzoyl peroxide, erythromycin and tetracycline.^{18, 19} One study compared 20% azelaic acid to 0.05% tretinoin over one month to report statistically equivalent comedone and total lesion reduction, and similar overall improvement with azelaic acid. Azelaic acid also demonstrated less erythema, scaling and irritation-induced discontinuation in comparison with tretinoin.¹⁷ Another trial comparing 20% azelaic acid with 5.0% BPO demonstrated a more rapid initial effect with BPO but similar results for global response and inflammatory lesion reduction at four months; finally, azelaic acid demonstrated milder, more transient adverse events than BPO.²⁰

Pooling together the results of four trials, Mackrides et al. determined that after six months of treatment, 65–85% of those treated with azelaic acid experienced a > 50% decrease in number of lesions and references as a “good to excellent clinical response.” Transient side effects lasting two to four weeks have been described. These include burning, erythema, dryness, scaling, pruritis and hypopigmentation.

Despite efficacy as a monotherapy, a large randomized trial demonstrated that azelaic acid functions better in combination.18 Subjects were randomized to a 12-week regimen of twice daily 20% azelaic acid cream, either as monotherapy or in combination with one of the following: 4% benzoyl peroxide gel twice daily, 1% clindamycin gel twice daily, 0.025% tretinoin cream once daily, or 3% erythromycin/ 5% benzoyl peroxide gel twice daily. All four regimens improved acne, achieving greater efficacy and patient satisfaction than azelaic acid monotherapy.