Lichenoid dermatitis due to chlorpromazine phototoxicity

A 75-year-old woman had lichenoid and bullous lesions in the sun-exposed areas. She had a history of cerebral embolism and received chlorpromazine (CPZ) until consultation at our clinic. Patch tests with CPZ were negative, but photopatch tests were positive at relatively high concentrations of CPZ and ultraviolet light radiation sites of 310, 340 and 370 nm. Rapid improvement of the lesions occurred upon discontinuation of CPZ and the avoidance of exposure to sunlight. From these results, the patient was considered to show lichenoid eruptions due to CPZ phototoxicity rather than photoallergy.