Case Report. Bullous tinea pedis in an elderly man.

We report a case of recurrent bullous tinea pedis that had been misdiagnosed for a long time and treated with oral steroids. Initially, direct microscopy of potassium hydroxide preparations was negative and culture did not reveal any fungal organism. In a biopsy taken simultaneously from the edge of a bulla and stained with periodic acid-Schiff, septate mycelia were clearly visible. Trichophyton mentagrophytes was later identified in repeated cultures. The infection resulted in two clinical variants of tinea: initially, the vesiculobullous type and later - after intake of steroids because of an unrelated disease - the dry squamous hyperkeratotic type. The change of the clinical pattern indicates the important role of the host's immune response in determining the clinical presentation of the disease.