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- Original article -
Onychomycosis and the Diagnostic Significance of Nail Biopsy
Chander Grover, Belum Siva Nagi Reddy and Krishnamoorthy Uma Chaturvedi*
Department of Dermatology and STD, Maulana Azad Medical College and Associated Hospitals.
*Department of Pathology, Maulana Azad Medical College and Associated Hospitals.
Onychomycosis is the most common cause of deformed nails. It is often confused clinically with other nail diseases such as psoriasis. A cross sectional study was carried out in 120 clinically suspected onychomycosis patients to assess the diagnostic utility of nail unit histopathology. The majority of the patients were males (72.5%) in the age group of 20-40 years (55%). Involvement of fingernails alone (37.5%) was found to be more common than toenails (12.5%). Distal and lateral subungual onychomycosis [DLSO] (76.6%) was the predominant morphological type noted. Direct microscopy with 10% potassium hydroxide (KOH) preparation revealed fungal filaments in 82.5% of the cases. Mycological culture on Sabouraud's dextrose agar with and without cycloheximide indicated fungal isolates in 44% of the cases, with Trichophyton mentagrophytes being the most common isolate (38.3%). The combined approach with KOH preparation and culture showed the evidence of fungus in 103 cases (85.8%). Of the rest of the 17 cases in whom both these procedures failed to confirm a diagnosis, nail unit biopsy was carried out in 15 consenting patients. Fungal hyphae (better demonstrable on PAS staining) were evident in 14 cases (93.3%). Other histopathological features observed among these patients were subungual hyperkeratosis, neutrophilic infiltrate, parakeratosis, hemorrhage, and serum crusts. We concluded that histopathological examination of nails is a valuable diagnostic aid in onychomycosis, especially if routine parameters fail to establish a diagnosis.
key words: onychomycosis; mycology; nail; histopathology; diagnostic utility
Received July 1, 2002; Accepted for publication December 3, 2002
Reprint requests to: Dr. B.S.N Reddy, Director Professor and Head, Type VI/2, MAMC Campus, Maulana Azad Medical College and Associated Hospitals, Bahadur Shah Zafar Marg, New Delhi-110002, India.
J Dermatol 30 (2): 116-122, 2003
Japanese Dermatological Association
http://www.dermatol.or.jp
