Mycological Profile of Onychomycosis: A Four-Year Retrospective Analysis from a Tertiary Care Center in South India

Introduction: Onychomycosis (OM) is the most common nail disorder, accounting for up to ۵۰% of nail dystrophies. The global prevalence of OM is ۵.۵%, and India has a reported prevalence ranging from ۰.۵% to ۵% across different regions. The most common agents of OM are dermatophytes, particularly Trichophyton rubrum and Trichophyton interdigitale. However, Indian literature shows considerable variability in the clinical presentations and the etiological spectrum. This study was conducted to determine the clinical presentations and mycological profile of OM in a tertiary care setting in South India. Methods: This retrospective descriptive study, conducted over a ۴-year period, reviewed records of patients attending the dermatology clinic with a clinical suspicion of OM from January ۲۰۲۰ to December ۲۰۲۳. Nail samples were processed using standard microscopic and culture methods. Results: Of the ۱۷۲ patients with clinically suspected OM included in the study, ۷۸ (۴۵.۳%) were laboratory-confirmed by potassium hydroxide (KOH) microscopy and/or fungal culture. Females predominated, with a male-to-female ratio of ۱:۱.۸. Fingernails were the most commonly affected site, with fingernail involvement observed in ۵۵.۸% of the clinically suspected cases. Distal lateral subungual onychomycosis (DLSO) was the predominant clinical presentation, accounting for ۵۵.۸% of the clinically suspected cases. Among the fungal isolates, Candida spp. were the most frequently isolated (۵۴.۷% of the ۶۴ culture-positive isolates), followed by Fusarium spp. (۲۵.۰%). Dermatophytes were isolated in only ۳.۱% of the culture-positive isolates (n = ۲, both identified as T. rubrum). Conclusion: This study demonstrates predominance of non-dermatophyte molds (NDMs) and Candida spp. over dermatophytes among culture-positive isolates in our specific tertiary care setting, which contrasts with several earlier Indian studies that reported dermatophyte predominance. These findings suggest that NDMs and Candida spp. may be important fungal isolates in OM in similar settings, although their pathogenic significance, particularly for NDMs and yeasts, requires careful clinical and laboratory correlation.

کلیدواژه ها:

Onychomycosis ، Candida ، Non-dermatophyte molds ، India ، Fusarium