Double-blind clinical study reveals synergistic action between alpha-hydroxy acid and betamethasone lotions towards topical treatment of scalp psoriasis

Objective A double-blind, single-site, split-face clinical study was organi zed and carried out in order to evaluate the efficacy, tolerability, and sa fety of a glycolic acid containing scalp lotion in conjunction with a betam ethasone (as the 17-valerate) scalp application against conditions of psori asis. Background alpha-hydroxy acids (AHA) have been proposed as therapeutic moda lities against skin exfoliative conditions such as ichthyosis, xeroderma, a nd psoriasis. AHAs are hereby clinically investigated as therapeutic modali ties adjuvant to corticosteroids in order to diminish systemic and topical adverse side-effects most frequently associated with use of the latter. Methods Twenty patients suffering from scalp psoriasis and other psoriatic conditions were included in a double-blind, split-fact clinical study, usin g combinations of a 10% (w/w) glycolic acid scalp lotion, placebo lotion (e xcipients only), and a 0.1% (w/w) betamethasone scalp application, applied twice daily without any bandage for a period of 8 weeks. Clinical assessmen ts were carried out by highly experienced physician evaluations based on a four-grade scale, prior to treatment and after 2, 4, 6 and 8 weeks. Results Improvement was observed in all cases included in the study followi ng treatment with the 10% glycolic acid lotion. However, when equal parts o f the 0.1% betamethasone lotion were combined, most of the treated sites we re healed. Moreover, the duration of treatment required for healing was in this case reduced to approximately half of that needed when the glycolic ac id or the betamethasone lotions were used separately for treatment. Conclusions The present clinical study demonstrates for the first time that the effective and well tolerated therapeutic efficacy of glycolic acid sca lp lotions is enhanced when used in conjunction with a 0.1% betamethasone s calp application against scalp psoriasis. This potential offers the practis ing dermatologist with novel treatment modes against severe skin conditions by combining topical corticosteroid with exfoliative agent therapy.