The authors describe an infectious disease, rarely occurring in the Slovak Republic-superficial trichophytia caused by Trichophyton tonsurans var. sulphureum-in a 37-year-old male patient with psoriasis. Untreated oval to circular foci 4-10 x 5-12 cm in size were localised on the forearms and knee, gradually developing black dots remaining after broken hair (parasitismus endothrix). After a failure in local and overall therapy by imidazole antibiotics, the peroral therapy by terbinafine (Lamisil) was successful. (Fig. 2, Ref. 19.)