Photoallergic contact sensitization to 6-methylcoumarin in poikiloderma of civatte

A 49-year-old woman presented with asymptomatic progressive erythema, hyperpigmentation, atrophy, and telangiectasia on her neck. The clinical appearance and histopathology of the skin lesion was consistent with poikiloderma of Civatte. Photopatch-testing with our standard photoallergens yielded a positive reaction to 6-methylcoumarin, which was found in the patient's perfume. This report describes the first case in which photoallergic contact sensitization to 6-methylcoumarin may play an important role in the pathogenesis of poikiloderma of Civatte.