Abstract
Members of the fungal genus Chaetomium usually colonize cellulose-containing plant remains but on rare occasions may cause opportunistic mycoses and cutaneous infection in otherwise healthy individuals. To our knowledge, there have been only five credible descriptions of onychomycosis caused by members of this genus and only two of these contained information on therapy. We describe the first case of Chaetomium globosum onychomycosis recorded in Spain. The etiologic significance of the fungus was confirmed by its repeated isolation at different times, to the exclusion of dermatophytes. Clinically, the affected nails showed an excellent response to terbinafine and complete cure appeared to have been attained.