A Case of Inltrating Erythema of the Trunk and the Limbs Associated with Acute Methotrexate Toxicity

Abstract

An 82-year-old woman was referred to our hospital with pruritic rash and mucocutaneous erosions. She had rheumatoid arthritis (RA), hypertension, and diabetes. She had taken 10 mg/week methotrexate (MTX) and 5 mg/week folic acid for the treatment of RA for 3 years. Four days before admission, she noted a pruritic rash on her trunk and limbs. Two days later, she developed dysphagia due to severe oral pain. On admission, physical examination revealed inltrating erythema of the left shoulder, back and lower limbs, and oral erosions on the lips and in the oral cavity. Blood tests demonstrated pancytopenia, anemia, inammation, and mild renal dysfunction. Based on histopathological ndings from the erythema on the left shoulder, vacuolar dermatitis and perivascular inammatory inltration of lymphocytes and eosinophils were conrmed. No apoptotic keratinocytes were detected in the epidermis. The patient was therefore diagnosed with acute MTX toxicity. We stopped MTX administration and performed‘leucovorin rescue’. The cause of the acute MTX toxicity in this case may have been the complex state of renal dysfunction, multipledrug usage, and old age. There was no history of inadvertent use of MTX or folic acid. Mucocutaneous erosions due to MTX may precociously indicate the development of other severe organ damage such as bone marrow suppression. Physicians should be aware of MTX-induced skin lesions to enable appropriate therapeutic action at an early stage and prevent the development of further complications. Skin Research, 18 : 22-26, 2019