The diagnosis of trachyonychia is often challenging, and misdiagnoses, particularly as onychomycosis, are common. 1-3 The correct diagnosis of trachyonychia is crucial because treatment options for trachyonychia include observation/active non-intervention, topical and systemic steroids, or immunomodulating agents, while onychomycosis should be treated with antifungal agents 1, 2 . Onychoscopy (nail dermoscopy) is a useful tool for various nail disorders. 4-8 However, a detailed morphologic analysis of trachyonychia has not been performed. Here, we aim to describe the characteristic dermoscopic features of trachyonychia and to explore whether these features are significantly different from those in onychomycosis. This article is protected by copyright. All rights reserved.