Photosensitive lichenoid reaction accompanied by nonphotosensitive subacute prurigo caused by carbamazepine.

A 58-year-old man developed a lichenoid reaction on light-exposed areas and subacute prurigo separate from the sun-exposed areas after receiving 200 mg of carbamazepine daily for one year. The difference action spectrum for erythema with or without ingesting the drug ranged from 250 to 390 nm with peaks at 260 and 290 nm. A positive photoingestion test was obtained after administering 2 mg of carbamazepine orally in one dose. Patch test with carbamazepine was negative, while photopatch test with carbamazepine was positive. Positive intracutaneous test was obtained with an irradiated mixture of human serum albumin and carbamazepine at 24 h and 48 h after injection. This patient appeared to be a case of photosensitive lichenoid reaction accompanied by nonphotosensitive subacute prurigo caused by carbamazepine.