A descriptive study of onychoscopic features in various subtypes of onychomycosis

The diagnosis of onychomycosis is usually clinical and is confirmed by 40% KOH examination. A diagnostic dilemma occurs when KOH examination is negative despite strong clinical suspicion. Dermoscopic evaluation of the nail is referred to as onychoscopy. We attempted to assess the dermoscopic findings in Onychomycosis positive with KOH examination.

A cross sectional study was conducted in a tertiary care center including 122 patients with clinical suspicion of onychomycosis with KOH positivity. After assessment of risk factors and gross nail examination, onychoscopic examination was done to identify the presence of the specific features.

Primary findings of onychoscopic examination were 'spiked pattern' in 80.3% subjects, of which 95 were distal lateral subungual onychomycosis (DLSO), 8 of total dystrophic onychomycosis (TDO). True leukonychia was seen in the single patient of proximal subungual onychomycosis (PSO) and pseudoleukonychia in the single patient of white superficial onychomycosis (WSO). Distal irregular termination was observed in 23% of subjects - 8 from DLSO and in all 20 patients of TDO. 'Ruin appearance' was observed in all 20 patients of TDO, 56 patients with DLSO and not seen in other types of onychomycosis (OM). Presence of spiked pattern, Longitudinal striae, Distal irregular termination and Ruin appearance were found to be statistically significant (p < 0.001).

In suspected onychomycosis, specific onychoscopic findings such as Spiked pattern, Longitudinal striae, Ruin appearance and Distal irregular termination can be used as supporting evidence for diagnosing onychomycosis clinically and initiating antifungal therapy if mycological testing is unavailable or negative.