Psoralen phototherapy and phototoxicity.

Psoralen therapy followed by exposure to long-wave ultraviolet (UV-A) light, a combination called PUVA therapy, stimulates pigmentation of the skin. PUVA therapy is effective in the treatment of vitiligo and hypopigmented scars. Because psoralens sensitize skin to UV-A light, phototoxic reactions are frequent. Patients with such reactions can present to the plastic surgeon because they clinically mimic thermal burns. We report a patient with vitiligo who treated herself with oral and topical psoralens and then exposed herself to sunlight. She developed an intense, burnlike reaction, with erythema, edema, and bullae. "Sunburn" may be a major injury in the psoralen user.