Publication:

Clinico-mycological study and comparison of efficacy of three different techniques of sample collection from skin lesions for potassium hydroxide mount preparation in dermatophytoses

Background Dermatophytoses are superficial fungal infections which invade and multiply within keratinized tissue. The KOH mount is one of the useful procedures and believed to be more reliable than culture for demonstrating dermatophytes. A few studies in the past have demonstrated the usefulness of alternative methods of sample collection for KOH preparation, but data on sensitivity and specificity of these methods is lacking. The aim of the study was to study the clinic-mycological aspects of dermatophytoses and to compare the efficacy of three different sampling techniques from skin lesions and correlating KOH mount with culture results.

Methods 210 clinically diagnosed patients with dermatophytic infection attending outpatient department of Dermatology of a tertiary care hospital for duration of 2 years (September 2015 to October 2017) were included. The samples were collected from skin, hair and nail. These samples were used for direct microscopy by KOH mount and fungal cultures by Sabouraud dextrose agar media.

Results Of the total of 210 patients, maximum were in age group of <10 years (74 cases), male: female - 1.2:1. Tinea corporis was commonest presentation (40.5%). Overall direct microscopy positivity was 81% while three different techniques from the glabrous skin and groins lesions was scraping method (97%), cellophane tape method (96%), skin surface biopsy (SSB) (98%) and culture in (89%). T. rubrum was commonest species isolate (37.7%).

Conclusions Tinea corporis was the commonest clinical type followed tinea capitis. T. rubrum were commonest dermatophytes isolated. All three methods of sampling were suitable for routine sample collection. The KOH mount helped rapid confirmation of clinical diagnosis.