Clinicomycological and Histopathological Profile of Onychomycosis: A Cross-sectional Study from South India

Onychomycosis (OM) is a fungal infection of the finger or toenails caused by dermatophytes, yeasts, or nondermatophyte molds (NDMs) and can involve any component of the nail unit. OM, apart from being asymptomatic, is a chronic disease and warrants long-term treatment.

The aim was to study the clinicoepidemiological features of OM and to evaluate the mycological and histopathological features among patients attending the dermatology outpatient department.

A cross-sectional hospital-based study was performed in 500 patients with symptoms related to the nails and nail folds. OM was confirmed in 284 patients by potassium hydroxide (KOH) mount, fungal culture, or biopsy. Descriptive analysis of the data was undertaken.

The study included 284 confirmed cases of OM of which 117 (41.1%) were positive for fungal elements by KOH mount, 168 (59.1%) samples showed positivity in fungal culture, and 62 (21.8%) samples had positive nail biopsy results. Distolateral subungual OM was the most common clinical type (47.6%). Among the fungal isolates, a predominance of dermatophytes was observed followed by yeasts and NDMs. The most common dermatophytic fungal isolate in the culture was Trichophyton rubrum (45%).

Our study implies the importance of laboratory diagnosis of OM as it can mimic diverse nail disorders. As the role of NDMs and yeasts is on the rise for etiology of OM, investigations such as KOH examination, culture, or nail biopsy becomes essential for correct diagnosis and management.