Objective: To assess the prevalence and risk factors of toenail onychomycosis and fungal foot infection in Thai diabetic patients.

Material and Method: This single center cross-sectional observational study recruited type 1 and type 2 diabetic patients older than 18 years who attended Siriraj Hospital between October 1, 2012 and November 30, 2013. Patient demographic data, clinical data, and medical history were collected by questionnaire and assessed. Diagnosis of fungal infection was confirmed by potassium hydroxide investigation and fungal culture was performed to identify the type of organism.

Results: One hundred forty four diabetes outpatients were enrolled and 38.9% were men. The mean (±SD) age was 59.6±12.7 years. Fungal infection was diagnosed 46 cases (31.9%). There were 28 cases (61%) with only toenail onychomycosis, two cases (4%) with only fungal foot infection, and 16 cases (35%) with co-infection (fungal foot infection and toenail onychomychosis). The organisms identified as causing fungal foot infection and toenail onychomycosis were dermatophytes (44.4% and 34.1%, respectively), non-dermatophytes (44.5% and 47.7%, respectively), and Candida species (5.6% and 4.5%, respectively). Risk factors found to be significantly correlated with toenail onychomycosis and fungal foot infection were male gender (p = 0.001), age older than 60 years (p = 0.006), agriculture-related activities (p = 0.006), family history of dermatophytosis (p = 0.034), and co-morbidity coronary heart disease (p = 0.044). No significant association was found for BMI, duration of DM, HbA1c, and diabetes related complications.

Conclusion: Prevalence of fungal foot and toenail infection in Thai diabetes patient was 31.9%. We found higher prevalence of non-dermatophyte organisms as the cause of dermatomycosis and toenail onychomycosis. Accordingly, clinical diagnosis without proper culture identification may result in treatment failure.

Keywords: Fungal foot infection, Toenail onychomycosis, Diabetes mellitus