Frequency, type and treatment of fungal pathogens in toenail onychomycosis in the central Alpine region of South Tyrol, northern Italy - a 10-year retrospective study from 2004 to 2013.

Onychomycosis is one of the most common dermatological diseases, primarily caused by dermatophytes, and sometimes, also by yeast and moulds. This study aims to clarify the frequency of isolated pathogens from mycotic toenails in the reference centre of the central Alpine mountain region of South Tyrol, northern Italy. Age and gender differences, types of pathogens and initial therapy used were also investigated. This is a retrospective study from 2004 to 2013 on the files of all patients with suspected onychomycosis in whom a cultural pathogen detection was performed. A total of 1565 patients were studied (943 women; 622 men), with a median age of 55 years. Fungal pathogens could be detected by culture in 49.5%. Significantly more pathogens could be grown in men (63.8%) than in women (39.9%, P < 0.0001). The most common pathogens grown were dermatophytes (53.3%), especially T. rubrum and T. interdigitale, followed by moulds (24.7%) and yeast (22%). Therapies prescribed were topical in 64.2% and systemic in 35.8% of the cases. Topical treatment was more frequent in older patients (P < 0.05). In northern Italy, dermatophytes are the most common causative agents for onychomycosis. Fungal pathogens were more commonly found in men than in women and topical treatment was more frequent in older patients.