A 57-year-old male carpenter living in Sagamihara, Kanagawa Prefecture, visited the Department of Dermatology of Kitasato University Hospital because an ulcer which appeared in his left forearm around May 1992 had spread gradually. An oval, shallow ulcer measuring 39 mm x 18 mm was found on the flexor aspect of the left forearm. Histopathological examination showed partial ulceration on the epidermis and marked cell infiltration throughout the entire dermal layer with an abscess in the centre and granulomatous reactions around it. PAS-positive spores were present between infiltrating cells and in giant cells in abscess and in granulomatous reactions. The skin lesion rapidly disappeared after beginning treatment with 125 mg day(-1) terbinafine and only a slight redness remained 14 weeks after starting the treatment. At this time the culture was negative. We conducted immunohistochemical examinations of the affected skin before, during and after starting treatment with terbinafine and studied local expression of cytokines at the affected lesion.