A retrospective cohort study of tinea pedis and tinea unguium in inpatients in a psychiatric hospital.

We conducted a retrospective cohort study on clinical and mycological features of tinea pedis and tinea unguium in psychiatric inpatients in Japan. Of the 317 inpatients (152 with schizophrenia and 165 with depression), 46.1% had tinea pedis and 23.7% had tinea unguium. Of those with tinea pedis, 48.6% also had tinea unguium. The most common clinical type of tinea pedis was the combination of interdigital type and hyperkeratotic type. The mean clinical score of tinea pedis was 5.9, and that of tinea unguium based on the Scoring Clinical Index for Onychomycosis (SCIO) was 15.8. The main causative species of tinea pedis were Trichophyton rubrum (68.4%) and T. mentagrophytes (26.3%). No statistically significant differences were observed in incidence rates of tinea pedis or tinea unguium between men and women or between patients with schizophrenia and those with depression. As for incidence rates by age, patients with depression showed a single peak for tinea pedis and / or tinea unguium in their 50's, while patients with schizophrenia exhibited twin peaks for tinea pedis and / or tinea unguium in their 50's and 70's. Both tinea pedis and tinea unguium tended to become more severe in patients with chronic schizophrenia. Our study suggests that schizophrenia and depression, like diabetes mellitus and HIV infections, should be regarded as risk factors for tinea pedis and tinea unguium.