In a horse with severe sweet itch and a history of corticosteroid treatment for this disorder,a single, well-circumscribed and crusty white lesion was present on the thigh. The geophilicdermatophyte species M. gypseum was cultured from the lesion. The lesion was treated topicallyonce a week with an enilconazole emulsion for four weeks. Full recovery was noted after twomonths. This case suggests that sweet itch combined with systemic corticosteroid treatment, mayact as predisposing factor for dermatophyte infection. In addition, the importance of correctisolation and identification of the causal agent is highlighted.