Corneofungimetry Bioassay on Malassezia spp. under Ketoconazole and Desonide Influences

Abstract

Background: Glucocorticoids can boost some Malassezia-driven dermatoses. However, both antifungals and topical corticosteroids improve lesions of seborrheic dermatitis. Objective: To revisit the topical activity of the antifungal ketoconazole and the corticosteroid desonide on Malassezia growth on human stratum corneum. Material and Methods: The computer-assisted corneofungimetry bioassay was used to compare the growth of M. furfur, M. globosa and M. restricta on human stratum corneum coated with olive oil. Four blinded gel formulations were tested. They contained either 2% ketoconazole, 0.05% desonide or a combination of 2% ketoconazole and 0.05% desonide; one gel was unmedicated. Untreated stratum corneum and specimens coated with a 2% ketoconazole cream were used as negative and positive comparators, respectively. A total of 45 samples (15 M. furfur, 15 M. globosa, and 15 M. restricta) were used for each test formulation in this randomized, double-blind study. Results: The 2% ketoconazole gel and cream and the combination of 2% ketoconazole and 0.05% desonide formulation abated similarly and significantly the M. furfur, M. globosa and M. restricta growth. The 3 species were similarly sensitive to these formulations. By contrast, no significant inhibitory effect was yielded by the 0.05% desonide gel and the vehicle. Conclusion: The presence of 0.05% desonide does not impair or improve the Malassezia susceptibility to 2% ketoconazole when growing on lipid-enriched human stratum corneum.