Accurate diagnosis of onychomycosis is important because its treatment is long-term, costly, and sometimes with complications. KOH test is quick and cheap but has low sensitivity. Hence, the need for additional tests such as culture and/or PAS. However, these two tests are not readily available and expensive. Dermoscopy is an emerging tool for the diagnosis of nail conditions.

This study aims to evaluate the accuracy of dermoscopy as a point-of-care tool in diagnosing distal subungual onychomycosis (DSO).

This is a prospective, cross-sectional study of 22 clinically diagnosed DSO patients selected via convenience sampling in a tertiary hospital from November 2019 to March 2021. Participants had gross nail examination, dermoscopy, KOH and PAS tests. Measures of diagnostic accuracy for the different dermoscopic patterns were obtained, with KOH and PAS results as reference standard.

Fifty-one nail samples were submitted for processing with only 49 nails accepted for analysis. The most common pattern was jagged edge with spikes (65.3%). Combining all 5 dermoscopic patterns increased the sensitivity to 91.2% (95% CI: 76.3, 98.1).

Dermoscopy may be used as a first-step, point-of-care tool in the diagnosis of DSO. Addition of mycological and histopathological tests is still warranted for confirmation.