title: Methotrexate induced false photosensitivity reaction.
abstract: Methotrexate is now being used in the treatment of a variety of intractable rheumatologic conditions. We report a patient with polymyositis who developed mild erythroderma after sun exposure. Forty-eight h later he received his weekly dose of methotrexate. Within 24 h the resolving rash erupted into an intense dusky red dermatitis with eventual formation of confluent bullae. The patient had a methotrexate induced ultraviolet reactivation reaction also known as a "false photosensitivity" reaction. This reaction has been reported in dermatologic publications but not in the rheumatologic literature.
mesh_terms: D006801:Humans; D008297:Male; D008727:Methotrexate / Q000009:adverse effects*; D008875:Middle Aged; D009220:Myositis / Q000188:drug therapy; D010787:Photosensitivity Disorders / Q000139:chemically induced* / Q000473:pathology
chemical_list: D008727:Methotrexate