The term "tinea incognita" refers to diverse clinical presentation of mycotic infections modified by inappropriate use of topical or systemic corticosteroids. A 67-year-old male patient with a five-year history of generalized erythematous plaques on the trunk and extremities, previously treated with topical corticosteroids, is described. The lesions mainly showed a psoriasiform, some eczematous appearance, few of them showing a clinical picture of folliculitis. The native mycologic specimen was negative. The diagnosis was made on the basis of mycologic culture finding of Trichophyton interdigitale growth. Systemic and topical antimycotic therapy administered for two months resulted in complete regression of skin lesions.