Fusarium onychomycoses in Switzerland—A mycological and histopathological study

Summary Onychomycoses in temperate climates are most commonly due to dermatophytes, particularly Trichophyton rubrum . Non‐dermatophyte nail infections are much less frequent, and their diagnosis requires a careful and repeated search for a potential dermatophyte that may have been overgrown in culture. A series of histological slides of suspected onychomycoses with uncommon fungal morphology prompted us to search for non‐dermatophytic moulds causing dermatophytosis‐like nail infections. Thirty cases were identified by culture as F solani , F oxysporum, F dimerum or F spp, and two more were only diagnosed histopathologically. None of these patients was immunocompromised. Treatment was mostly unsuccessful with terbinafine whereas itraconazole showed a moderately better treatment result; in all cases, a topical ciclopirox nail varnish in a hydroxychitosan base was added.