Factors influencing coexistence of toenail onychomycosis with tinea pedis and other dermatomycoses: a survey of 2761 patients.

OBJECTIVE: To evaluate the prevalence and factors influencing the presence of concomitant dermatomycoses in patients with toenail onychomycosis.

DESIGN: Prospective study based on a specially designed questionnaire completed by dermatologists.

PATIENTS: A total of 2761 patients with toenail onychomycosis.

MAIN OUTCOME MEASURES: The diagnosis of fungal skin infections was confirmed by direct microscopic examination or by culture.

RESULTS: In 1181 patients (42.8%) with toenail onychomycosis, concomitant fungal skin infections were noted. Tinea pedis was the most common and was found in 933 patients (33.8%). Other concomitant fungal skin infections were fingernail onychomycosis (7.4%), tinea cruris (4.2%), tinea corporis (2.1%), tinea manuum (1.6%), and tinea capitis (0.5%). The presence of concomitant fungal skin infections depended on number of involved toenails; duration of onychomycosis; sex, age, and education level; area of residence; and type of isolated fungus.

CONCLUSIONS: The coexistence of toenail onychomycosis with other types of fungal skin infections is a frequent phenomenon. It could be hypothesized that infected toenails may be a site from which the fungal infections could spread to other body areas. Effective therapy for onychomycosis might therefore be essential not only to treat the lesional toenails but also to prevent spreading the infection to other sites of the skin.