Dermoscopic Patterns of Onychomycosis: A Cross-sectional Study in One Institution

Background: Several dermoscopic findings that could be helpful in diagnosing onychomycosis have been reported in many cases, but they have not been sufficiently utilized in clinical practice. Objective: To evaluate and identify the dermoscopic findings that may assist in the accurate diagnose of onychomycosis. Methods: The study included 42 patients with clinical features suggestive of onychomycosis based on the clinical history, physical examination, dermoscopic findings, and mycological investigation. Clinical photographs and nail dermoscopy images were obtained, which were retrospectively reviewed and analyzed according to the onychomycosis classification. Results: In total, 42 representative nails were reviewed. Common dermoscopic patterns such as yellow/brown discoloration and subungual hyperkeratosis were found in our onychomycosis patients. Key findings observed in specific subtypes were distolateral subungual onychomycosis with "jagged edges with spikes", proximal subungual onychomycosis or white superficial onychomycosis with irregularly bordered homogeneous leukonychia with postinflammatory hyperpigmentation on the proximal nail fold, and fungal melanonychia with nail plate roughness and nail fold hyperkeratosis. Conclusion: Our study, along with previous studies, demonstrated dermoscopy as a quick and effective tool for diagnosing onychomycosis. In addition, periungual dermoscopic findings can be an important clue in onychomycosis diagnosis, especially in cases of fungal melanonychia and leukonychia.