Unilateral segmental Darier's disease (DD) is a rare variant of DD that presents with erythematic lesions in a unilateral distribution without other associated features of DD. Although diagnosis is challenging, unilateral segmental DD should be considered for an acantholytic dermatosis in a unilateral distribution and a history of neuropsychiatric disorders.
Keywords: Darier's disease; Grover's disease; Hailey‐Hailey.