Failure of clotrimazole-betamethasone dipropionate cream in treatment of Microsporum canis infections

Abstract

The use of antifungal-steroid combination topical medications carries a theoretic advantage of rapid symptomatic relief. At the same time, these drugs possess several potential disadvantages, including steroid-related adverse effects (such as atrophy, telangiectasia, and acneiform eruptions) and steroid impairment of natural defenses facilitating infection and thereby interfering with the expected efficacy of the antifungal component. Although steroid-related complications would most likely result from prolonged use or abuse of combination agents, treatment failures could theoretically appear even with proper drug use. The latter actually appears to be relatively rare. As documented in a review, the use of proprietary clotrimazole-betamethasone dipropionate offers similar mycologic and clinical cure rates when compared with a variety of single-agent antifungal drugs in the management of tinea pedis, tinea cruris, and tinea corp0ris.l We report a small series of therapeutic failures associated with use of a steroid-antifungal medication. Of particular interest, all cases treated were caused by Microsporum canis.