Reactivation of a subsiding sunburn after the administration of methotrexate is an unusual event about which little has been written. Although methotrexate is known as a potentially photosensitizing drug,1 the exact nature of this phenomenon is not understood. Since methotrexate often is used in the treatment of psoriasis, it is important that dermatologists be aware of the peculiar reaction reported herein.
Report of a Case
A previously healthy 32-year-old woman underwent a hysterectomy in January 1977 for choriocarcinoma of the uterus. Two months later, chemotherapy with methotrexate was begun. Every other week she received methotrexate, 2.5 mg/day orally, for seven consecutive days.In June 1977, after working in her garden, the patient had a mild erythema develop on the sun-exposed areas of her back and arms. The sunburn occurred during a week in which she was not receiving methotrexate. Two days after this sun exposure, she resumed receiving methotrexate.
Korossy KS, Hood AF. Methotrexate Reactivation of Sunburn Reaction. Arch Dermatol. 1981;117(5):310-311. doi:10.1001/archderm.1981.01650050066027