Clinico–mycological correlation of onychomycosis: emphasizing the role of non-dermatophytes in a tertiary care hospital from Karnataka, India

Onychomycosis is a widespread problem in the clinical practice of dermatology, caused by dermatophytes, yeasts, and non-dermatophyte molds. In India, relatively little work has been done on this problem. It is a known fact that the geographical distribution of the fungi may change from time to time. Hence, through this study, an attempt was made to identify the clinical patterns and causative agents of onychomycosis. This study was conducted on 100 clinically suspected onychomycosis patients. The necessary clinical details were noted with their consent. Nail clippings were collected from the most severely affected parts and were subjected to direct microscopy in 40% potassium hydroxide before being inoculated into Sabouraud’s dextrose agar with and without cycloheximide at 25 °C and 37 °C for up to four weeks. Growth was identified following the standard protocols by assessing the rate of growth, colony character, lactophenol cotton blue mount, slide culture, urease test, germ tube test, etc. Among the 100 patients, the mean age was 40.8 years. The male/female ratio was 1.28:1. Fingernail (49%) involvement was more common than toenail involvement (32%). Distal lateral subungual onychomycosis (52%) comprised the predominant clinical pattern.  KOH mount was positive in 46%, while the culture was positive in 44% of patients. The causative agents isolated were non-dermatophyte molds (63.6%), dermatophytes (18.2%), and yeasts (18.2%). This work shows the broad spectrum of causative agents of onychomycosis with non-dermatophyte molds as the predominant isolates.