Phytophotodermatitis: a phototoxic cutaneous reaction to recognise

Abstract

A 22-year-old woman presented with hyperpigmented lesions that had evolved over four days. The initial lesions appeared as erythematous patches on the dorsal hands, panel A multiple hyperpigmented macules and patches on the dorsal left hand and, within 24 hours, extended to the chest and abdomen, panel B hyperpigmented patch on the upper abdomen with an area of focal reabsorption of a small bulla. All lesions were painless, and non-pruritic, ranging from <1 cm to 4 cm in diameter. She had no relevant medical history or chronic medication use. A detailed history revealed unprotected skin contact with lime juice six days earlier, followed by sun exposure. Based on lesion distribution and clinical history, a presumptive diagnosis of phytophotodermatitis was established. Topical corticosteroid therapy led to marked improvement, as expected.

Phytophotodermatitis is a phototoxic reaction triggered by furocoumarins present in plants such as lime, celery, and parsley upon ultraviolet exposure 1,2. Lesions typically peak within 72 hours post-exposure, and clinical manifestations may vary widely 2,3. Recognition of this condition is essential to avoid misdiagnosis as infectious or autoimmune dermatoses.