Solar urticaria

Abstract

Solar urticaria (SU) is an uncommon photodermatosis, which is an immediate-type hypersensitivity reaction, usually to UVA (320–400 nm) and visible (400–700 nm), less often to UVB (290–320 nm) and rarely to infrared radiation. It is characterized by itching, erythema, and whealing over sun-exposed sites, which, when severe, cause significant lifestyle restriction. It is usually idiopathic but can be seen in association with porphyria, drugs, and topical tar.