Are local and systemic conditions important for the development of onychomycosis?

Available epidemiological data indicate that the prevalence of onychomycosis due to dermatophytes increases with ageing. The aim of this study was to investigate the epidemiology of dermatophyte nail infections in 2 populations selected only on an age basis and to verify whether the presence of onychomycosis was associated with increased exposure to possible predisposing factors. From January to June 1995, the nails of 1,800 military recruits and 253 elderly individuals living in a nursing home were examined. Mycological studies were performed in all cases of suspected onychomycosis. The presence of systemic or local diseases that may favor fungal nail infection as well as exposure to environmental factors were assessed in the 2 populations. Onychomycosis was diagnosed in 8 recruits (0.44%) and 38 of the elderly people (15%). The presence of onychomycosis was not related to the degree of exposure to environmental factors or to systemic or local diseases.