The Role of Scanning Electron Microscopy in the Direct Diagnosis of Onychomycosis

PURPOSE: The purpose of this study was to evaluate the role of scanning electron microscopy (SEM) in the direct diagnosis of suspected onychomycosis with negative mycological test results. METHODS: Outpatients diagnosed with suspected onychomycosis with negative mycological test results, including direct microscopic examination with 10% potassium hydroxide (KOH) and fungal culture, on 3 separate occasions were recruited. A small piece of infected nail was obtained for SEM examination. RESULTS: Among the 48 suspected onychomycosis samples, SEM revealed that 18 (37.5%) were positive for fungal structures, including 10 (20.8%) cases of hyphae and 8 (16.7%) cases of yeast blastospores or budding. CONCLUSION: SEM represents an effective method to diagnose suspected onychomycosis when the traditional mycological methods were negative. Therefore, this technique could be used in clinical practice.