Epidemiology of onychomycosis in Crete, Greece: a 12-year study.

Onychomycosis is a chronic fungal nail infection caused by dermatophytes, yeasts or non-dermatophyte moulds (NDMs). It occurs worldwide and accounts for about 50% of all nail disorders. The incidence of the disease and the prevalence of pathogens involved vary in different geographical areas and change with time. This study was undertaken to determine the epidemiology of onychomycosis in Crete, Greece during a 12-year period. Mycologic nail investigation (direct microscopy and cultures) was performed in samples taken from 3317 patients with clinical suspicion of onychomycosis. Demographic characteristics, comorbidities and concurrent superficial fungal infections at other body sites were also recorded. Onychomycosis was mycologically confirmed in 547 (16.5%) patients. Fingernail onychomycosis was found in 274 (50.1%) patients, toenail onychomycosis in 271 (49.5%), and both toenail and fingernail onychomycosis in two (0.4%). Yeasts were the major causative agents, followed by dermatophytes and NDMs. Candida albicans was the most commonly isolated yeast species and Trichophyton rubrum the most common dermatophyte. Concomitant fungal skin infections were noted in 53 (19.6%) patients with toenail onychomycosis. Factors predisposing to onychomycosis were trauma, diabetes, psoriasis, peripheral circulatory insufficiency and immunosuppression. Mycological investigations are necessary to confirm clinical diagnosis and identify the pathogen, in order to select the most appropriate treatment.