A typical methotrexate dermatitis in a patient suffering from rheumatoid arthritis [Su di un caso inconsueto di dermatite da metotrexate in un paziente affetto da artrite reumatoide]

Methotrexate has been implicated in a variety of cutaneous adverse reactions including alopecia, hyperpigmentation, urticaria, small vessel vasculitis, false photosensitive reaction and porphyria cutanea tarda. We report a case of a patient with rheumatoid arthritis, who, five days after the second methotrexate injection, presented with mouth ulcers and cutaneous manifestations; these last were characterized by non pruriginous, purpuric, erythematous and confluent patches localized over the right hip and left shoulder, with a metameric distribution. We clinically excluded anaphylaxis, urticarial or purpuric reactions and based diagnosis on the histological findings showing a leukocytoclastic vasculitis. This report led us to conclude that a small vessel angiitis may also present after a low dose of methotrexate and that cutaneous reactions to the drug are not uncommon.