Photosensitivity Due to a Fluorouracil Derivative

A photosensitive lichen planus-like eruption developed in a 63-year-old man during postoperative chemotherapy with 1-(2-tetrahydrofuryl)-5-fluorouracil. The action spectrum for the photosensitivity was in the long-wave ultraviolet light (UV-A). The reaction was reproducible on readministration of the drug and exposure to UV-A. At the time of this test, a flare-up phenomenon was observed at previously involved sites. The photopatch test was negative with the drug. Patients taking the drug who had no dermatitis were not sensitive to UV-A. These observations suggest that the photosensitivity that occurred in the patient was possibly photoallergic.