Diagnosis and management of longitudinal erythronychia: A clinical review by an expert panel.

Longitudinal erythronychia (LE) is defined as a longitudinal red band of the nail(s) and is classified as localized (involvement of 1 nail) or polydactylous (involvement of more than 1 nail). The differential diagnosis is distinct for these classifications. The etiologies of localized longitudinal erythronychia are most frequently benign subungual neoplasms and less often malignancies. Polydactylous longitudinal erythronychia is typically secondary to regional or systemic diseases, including lichen planus and Darier disease. LE is a common but underrecognized clinical finding. Increased dermatologist awareness of the clinical characteristics and differential diagnosis for LE is necessary given the possibility for malignancy and associated systemic disease. In this clinical review, the clinical features, differential diagnosis, evaluation, and management of LE are described.