Habitual Thumbsucking-induced Koilonychia in Infancy / 대한피부과학회지

ABSTRACT

Koilonychia is dystrophy characterized by eversion of the marginal portion of the nail. As a result, the central portion of the nail is concave. It has been associated with systemic or skin-related conditions. Hereditary koilonychia is inherited as an autosomal dominant trait. Koilonychia can also be caused by exogenous factors such as certain toxic chemicals or repeated mechanical trauma. In this case, koilonychia on the fingernail of the left thumb was caused by repeated trauma resulting from continuous suction since birth. Herein, we report a rare case of koilonychia induced by habitual thumbsucking.