The causative pathogens of onychomycosis in southern Taiwan

Selecting an appropriate antimycotic targeting the pathogens are among the most important factors for successfully treating onychomycosis. The aim of this study was to investigate the pathogens of onychomycosis in southern Taiwan and analyse the association between various factors and the distribution of pathogens. A total of 375 patients with onychomycosis were enrolled. Histopathological examination and fungus culture of nail specimens were performed. The pathogens were dermatophytes in 227 patients (60.5%), Candida in 118 (31.5%) and moulds in 30 (8%). Compared to patients with toenail involvement, the odds ratio (OR) for those with fingernail involvement to have non-dermatophytic onychomycosis (NDO), i.e. onychomycosis caused by Candida and moulds, was 5.04 [95% confidence interval (CI): 2.21-11.15], and the OR for those with fingernail and toenail involvement to have NDO was 2.66 (95% CI: 1.61-4.34). The F/M OR to have NDO was 2.36 (95% CI: 1.51-3.61), and 9.80 for diabetics (95% CI: 1.01-106.85). The OR for patients with paronychia to have NDO was 10.33 (95% CI: 5.61-18.88) compared to those without paronychia. Compared to patients with a non-wet occupation, the OR for those with a wet occupation to have NDO was 4.76 (95% CI: 2.01-11.16). The distribution of pathogens significantly varies with the involved sites, patients' gender and occupation, and presence of diabetes mellitus or paronychia. In contrast to temperate western countries, NDO is more prevalent in the tropics and subtropics including southern Taiwan.