Prevalence of foot diseases in outpatients attending the Institute of Dermatology, Bangkok, Thailand

Two thousand patients who visited the outpatient department at the Institute of Dermatology, Bangkok, were assessed for the presence of foot diseases by questionnaire and physical examination. Abnormalities were detected in 741 individuals (37.1%). Nonfungal conditions were more prevalent (31.4%), mainly consisting of eczema (254 cases, 12.7%) and psoriasis (176 cases, 8.8%). Fungal disease was observed in 119 cases (6.0%). There were 76 cases (3.8%) with tinea pedis and 33 cases (1.7%) with onychomycosis. The identified organisms causing tinea pedis were 57.9% nondermatophyte moulds, 36.8% dermatophytes, and 2.6%Candida spp. The corresponding organisms causing onychomycosis were 51.6% nondermatophyte moulds, 36.3% dermatophytes, and 6.0%Candida spp. Among nondermatophytes, Scytalidium dimidiatum was the leading pathogen while Trichophyton rubrum and T. mentagrophytes were the predominant dermatophytes identified. Diabetes mellitus, peripheral vascular disease and activities related to foot trauma were noted to be predisposing factors for onychomycosis. Footwear, particularly sandals and cut shoes, was the only factor relevant to individuals with tinea pedis (P < or = 0.05). In contrast with other published data on fungal foot infections, this study disclosed a higher prevalence of nondermatophyte organisms, predominantly S. dimidiatum, as the major cause of tinea pedis and onychomycosis. An increase in awareness is necessary to identify such cases, prevent misdiagnosis and initiate appropriate treatment.