Superficial mycosis is a frequent cause of consultation in Dermatology and General Medicine. The microbiological studies of this fungal condition are important not only to do the differential diagnosis, but also to establish the causing agent of the disease as well as its epidemiological aspects and the treatment. In this study 265 skin and nail samples have been collected from individuals at the Laboratory of Medical Mycology of School of Microbiology, Costa Rica University. Nail diseases represent 67,5% of the total cases studied. Trichophyton rubrum was the most frequent isolated fungus; also, other dermatophytes and Candida sp. were isolated from nail and skin. Fusarium sp., a filamentous nondermatophyte fungus, was isolated from both finger and toe nails. This finding is of relevant, since Fusarium sp., an emergent etiological agent of onychomycosis, does not respond well to treatment based on fluconazol.

superficial mycosis; onychomycosis; dermatophytes; Fusarium