To the Editor:
A 71-year-old Hispanic man with a history of vitiligo presented with an acute-onset blistering rash on the face, arms, and hands. Physical examination demonstrated photodistributed erythematous plaques with overlying vesicles and erosions with hemorrhagic crust on the face, neck, dorsal aspects of the hands, and wrists (Figure). Further history revealed that the patient applied a new cream that was recommended to treat vitiligo the night before the rash onset; he obtained the cream from a Central American market without a prescription. He had gone running in the park without any form of sun protection and then developed the rash within several hours. He denied taking any other medications or supplements. The involvement of sun-protected areas (ie, upper eyelids, nasolabial folds, submental area) was explained when the patient further elaborated that he had performed supine exercises during his outdoor recreation. He brought his new cream into the clinic, which was found to contain prescription-strength methoxsalen (8-methoxypsoralen), confirming the diagnosis of acute phototoxic contact dermatitis. The acute reaction had subsided, and the patient already had discontinued the causative agent. He was counseled on further avoidance of the cream and sun-protective measures.
8-Methoxypsoralen–induced phototoxic contact dermatitis. Photodistributed erythematous plaques with overlying vesicles and erosions with hemorrhagic crust as well as background depigmented patches of vitiligo.
The photosensitizing properties of certain compounds have been harnessed for therapeutic purposes. For example, psoralen plus UVA therapy has been used for psoriasis and vitiligo and photodynamic therapy for actinic keratoses and superficial nonmelanoma skin cancers.1 However, these agents can induce severe phototoxicity if UV light exposure is not carefully monitored, as seen in our patient. This case is a classic example of phototoxic contact dermatitis and highlights the importance of obtaining a detailed patient history to allow for proper diagnosis and identification of the causative agent. Importantly, because prescription-strength topical medications are readily available over-the-counter, particularly in stores specializing in international goods, patients should be questioned about the use of all topical and systemic medications, both prescription and nonprescription.2