A comparison of direct microscopy and culture with periodic acid schiff staining in the diagnosis of onychomycosis

Introduction and Objectives: Onychomycosis, or fungal infection of the nail apparatus by dermatophytes or nondermatophytes, is more than just a cosmetic problem. Dermatophytes are known to cause 90% of toenail and atleast 50% of fingernail onychomycosis. Our study offers insight into the unique current epidemiological aspects of onychomycosis in our region, including the less known nondermatophytemolds;. Since histopathology of nail clippings using Periodic Acid Schiff is clearly an invaluable tool in diagnosing onychomycosis, we integrated and comparatively evaluated it with the tests of routine mycology for the same. Materials and Methods: Patients in Rajarajeswari Medical College and Hospital (a tertiary care hospital) presenting with clinically apparent onychomycosis were included in this study. Each specimen of subungual debris and nail clippings was divided into two portions- one for direct microscopy and the other for culture. Nail clippings alone were used for PAS staining. Results: The present study was carried out on 40 clinically suspected cases of onychomycosis in the Department of Microbiology, Rajarajeshwari Medical College and Hospital over a period of one year. Out of 40 samples, 14(35%) samples showed fungal elements in 20% KOH, in 12(30%) samples fungal culture was positive and 19(47.5%) were PAS stain positive. Out of 12 isolates, 5(41.6%) were dermatophytes and 7(58.4%) were nondermatophytes. Keywords: KOH, PAS, Dermatophytes, Nondermatophytes, Nail infection, Onychomycosis.