Distinct Onychoscopic Patterns in Clinical Variants of Onychomycosis: Insights from a South Indian Tertiary Care Centre

Background: Onychomycosis is an infection of the nail unit caused by fungi. Onychoscopy is a quick, non- invasive, office-based diagnostic tool for the examination of nail unit and its components by magnification, using a dermoscope enabling observation of nail features that are not visible to the naked eye. Certain dermoscopic patterns demonstrate 100% specificity for onychomycosis. This study aims to contribute towards the development of onychoscopy based diagnostic criteria for onychomycosis in the near future. Objective: To identify the onychoscopic patterns in confirmed cases of onychomycosis and the association between the onychoscopic patterns and the clinical variants of onychomycosis. Materials and Methods: 80 cases of clinically diagnosed onychomycosis who tested positive for fungus by either microscopy or culture were subjected to onychoscopic examination with a 150x magnification dermoscope. Results: The most common onychoscopic pattern associated with onychomycosis was distal irregular termination (37.5%). DLSO nails were significantly associated with longitudinal striae (38.3%), distal irregular termination (34.7%) and jagged proximal edge (28%). TDO nails were significantly associated with ruin pattern (68.6%) and lamellar microsplitting (60%). Cloud pattern (83.3%) was found to be significantly associated with PSO. WSO had a significant association with grid pattern (100%). The newly reported blue globules was also observed in this study. Conclusion: The most common onychoscopic pattern associated with onychomycosis was distal irregular termination. This study was also able to establish significant relationship between individual clinical variants of onychomycosis and some of the onychoscopic patterns.