A study to compare and classify etiological agents of onychomycosis

Abstract

Abstract Background Onychomycosis, the condition that was always regarded as merely a cosmetic problem, now has become an important medical issue. Etiological prevalence of onychomycosis varies subject to the population demography, geographical location or the mycological technique used for the diagnosis. Aim This study aims to identify and classify the fungal etiology of onychomycosis from a tertiary care hospital of north India over a duration of two years. Methods The study included 169 clinically suspected patients of onychomycosis. The fungal etiology was determined by direct examination in 20% KOH after overnight incubation at 37 °C and culture on Sabouraud’s Dextrose Agar. Results 135 (79.9%) out of the total patients were confirmed cases of onychomycosis as per the diagnostic criteria. Hyaline hyphomycetes were the most common group of fungi isolated (50.0% of all fungal isolates) with only 15.4% isolates of the classical dermatophytes. A positivity of 18.3% and 78.7% by KOH examination and culture respectively was reported. .A sensitivity and specificity of 21.48% and 100% was found for KOH positivity; though culture was 98.52% sensitive and 82.35% specific. Conclusions Hyaline hyphomycetes are a common cause of onychomycosis. KOH examination can not be relied upon for diagnosis of onychomycosis, for which fungal culture appears to be an appropriate choice along with KOH examination.