Prevalence and risk factors of tinea unguium and tinea pedis in the general population in Spain

This study prospectively evaluated the prevalence and risk factors of tinea unguium and tinea pedis in the general adult population in Madrid, Spain. One thousand subjects were clinically examined, and samples of nails and sc ales from the interdigital spaces of the feet were taken from those patient s presenting with signs or symptoms of onychomycosis and/or tinea pedis, re spectively. In addition, a sample from the fourth interdigital space of bot h feet was collected from all individuals with a piece of sterilized wool c arpet. Tinea unguium was defined as a positive direct examination with pota ssium hydroxide and culture of the etiological agent from subjects with cli nically abnormal nails. Patients with positive dermatophyte cultures of foo t specimens were considered to have tinea pedis, The prevalence of tinea un guium was 2.8% (4.0% for men and 1.7% for women), and the prevalence of tin ea pedis was 2.9% (4.2% for men and 1.7% for women). The etiological agents of tinea unguium were identified as Trichopyton rubrum (82.1%), followed b y Trichopyton mentagrophytes var. interdigitale (14.3%) and Trichopyton ton surans (3.5%). Trichophyton rubrum (44.8%) and Trichophyton mentagrophytes (44.8%), followed by Epidermophyton floccosum (7%) and T. tonsurans (3.4%), were the organisms isolated from patients with tinea pedis. The percentage of subjects who suffered simultaneously from both diseases was 1.1% (1.7% for men and 0.6% for women). In a multivariate logistic regression analysis , age (relative risk [RR], 1.03) and gender (RR, 2.50) were independent ris k factors for tinea unguium, while only gender (RR, 2.65) was predictive fo r the occurrence of tinea pedis. In both analyses, the presence of one of t he two conditions was associated with a higher risk for the appearance of t he other disease (RR, >25).