Background and Purpose: Hot and humid climate of Vietnam favors fungal infections; however, data on
toenail onychomycosis in this region remain limited. In this regard, the present study aimed to investigate risk factors, clinical features, and causative agents of
toenail onychomycosis in Vietnam. Materials and Methods: This cross-sectional study was conducted in Nghe An province, Vietnam, from March ۲۰۲۱ to August ۲۰۲۲. Toenail samples from female traders with suspected onychomycosis underwent direct examination and culture. Isolates were identified using conventional and molecular techniques, including restriction fragment length polymorphism analysis and sequencing of the internal transcribed spacer region. Results: Based on findings, ۴۵.۵% of ۲۲۴ participants were diagnosed with onychomycosis. The identified
risk factors for onychomycosis were water contact (odds ratio (OR) ۲.۴۳۴; ۹۵% confidence interval (CI) ۱.۰۹۸–۵.۳۸۳) and nail grooming (OR: ۲.۰۹۶; ۹۵% CI: ۱.۰۰۲–۴.۳۸۴). Distal and lateral subungual onychomycosis was the most common form (۸۴.۳%), followed by superficial white (۸.۸%) and proximal subungual form (۶.۹%). Most cases were classified as mild (۳۵.۳%) or moderate (۴۰.۲%) infections, with an average onychomycosis severity index (OSI) score of ۱۰.۲۵ ± ۸.۰۹. Yeasts accounted for ۷۰.۶% of cases, and Candida was the leading genus (۵۴.۹%), followed by Trichosporon (۱۳.۷%) and Geotrichum (۱.۹%). Most mold-related cases were caused by non-dermatophyte fungi, including Aspergillus (۱۶.۷%), Penicillium (۵.۹%), Curvularia (۲.۹%), Fusarium (۲.۰%), and Talaromyces (۱%), while dermatophyte (Trichophyton) was identified in only one case (۱%). Compared with yeast infections, mold-related cases were more associated with older participants and a higher rate of severe cases (۴۳.۳% vs. ۱۶.۷%, p = ۰.۰۱۰) as well as OSI score (۱۳.۶ ± ۸.۲ vs. ۸.۸ ± ۷.۷, p = ۰.۰۰۶). Conclusion: Both behavioral and occupational factors were risks for toenail onychomycosis, which was mostly mild to moderate and associated with yeasts. Non-dermatophyte molds were less frequent but linked to more severe cases. Targeted prevention and tailored treatment strategies are needed.
