Comparative evaluation of KOH mount, fungal culture and PAS staining in onychomycosis
Keywords:KOH mount, Fungal culture, PAS, Onychomycosis
Background: Onychomycosis is a common ailment associated with significant physical and psychological morbidity. Increased prevalence in the recent years has attributed to enhanced longitivity, co morbid conditions like diabetes, avid spots participation and emergence of HIV. The objective of the study was to evaluate KOH mount, fungal culture and PAS staining of affected nail plate in diagnosis of onychomycosis.
Methods: The present study was carried out in OPD of Dermatology, PESIMSR, Kuppam, Andhra Pradesh during the period of October 2010 to October 2012 including all patients showing classical clinical features of onychomycosis.
Results: Majority of patients were from 21-40 years age group i.e. 46%. 56% of finger nails were commonly involved than 36% toe nails. DLSO is the most common clinical variant accounting for 80%. Most common isolated species as Trichophyton rubrum (31.6%) followed by T. mentagrophytes and Aspergillus niger 15.8% each. The sensitivity of KOH (81.82%), PAS (84.56%) and culture 57%. Both PAS and KOH were more sensitive than culture (p<0.001). PAS was also more sensitive than KOH. The specificity of KOH 92.86%, culture 92.86% and PAS 57.14%.
Conclusions: Fungal culture though is the gold standard for the identification of pathogens but it takes minimum 2-3 weeks. Histopathological examination of nail clippings with PAS stain is simple, highly sensitive screening test.
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