Histopathology of Hair Follicle Epithelium in Patients of Recurrent and Recalcitrant Dermatophytosis: A Diagnostic Cross-Sectional Study

CONTEXT: Recurrent and recalcitrant dermatophytosis is a major evolving health problem in India. Histopathology is important in the diagnosis of recurrent and resistant cases, as it is postulated that hair follicle epithelium is affected, acting as the reservoir leading to recurrence and recalcitrance. AIMS: This study aims to study histopathology of hair follicle epithelium in patients of recurrent and recalcitrant dermatophytosis. SETTINGS AND DESIGN: A diagnostic cross-sectional study was performed at tertiary care hospital and referral center in central India. MATERIALS AND METHODS: A 3 mm-sized punch skin biopsy was taken from 108 patients of recurrent or recalcitrant dermatophytosis involving hair follicles. Sections were stained by hematoxylin and eosin (H and E) stain in these patients followed by special stains such as periodic acid–Schiff (PAS) stain and Gomori methenamine silver (GMS) stain in 78 individuals where hair follicle was seen on H and E stain. RESULTS: In H and E stain, surface epidermis fungus was observed in 57/108 patients (52.7%). In hair follicle-positive sections (78), surface fungus was seen in 52.6% with H and E stain, 84.6% with PAS stain, and 91% with GMS stain. H and E was 62.12% sensitive and 100% specific to diagnose fungus when compared with PAS stain and 57.7% sensitive and 100% specific when compared with GMS stain. PAS was 91.5% sensitive and 85.7% specific when compared with GMS stain. Ectothrix infection was the most common form of hair infection observed in 87.2% cases with GMS stain. Simultaneous presence of fungus in hair follicle and stratum corneum was observed in 87.3% of patients. CONCLUSION: Majority of patients showed affection of hair follicles by dermatophytes in clinically chronic, recurrent, and recalcitrant dermatophytic infections. GMS stain is the acceptable gold standard for detection of fungal elements.