Retronychia: A Common and Misdiagnosed Condition

We report the case of two patients who consulted because of yellowing and thickening of their toe nails, with several relapses throughout time. Hand nails were unaffected. Both patients presented negative potassium hydroxide test and fungus culture, which excluded a diagnosis of onychomycosis. Further examination showed signs of trauma and growth of several overlapping nail plates, which lead to the diagnosis of retronychia, a common but misdiagnosed condition. We aim to emphasise the clinical aspects and possible treatments available for these types of cases.