Methotrexate-induced epidermal necrosis.

Methotrexate-induced epidermal necrosis is a rare, potentially fatal mucocutaneous reaction that clinically mimics Stevens-Johnson syndrome/toxic epidermal necrolysis. Early clinical manifestations include leukopenia, thrombocytopenia, mucositis and skin erosions. Risk factors for methotrexate-induced epidermal necrosis include age greater than 60 years, chronic kidney disease, and high initial dose of methotrexate (>10 mg/weekly) without folic acid supplementation. A 63-year-old female with a history of psoriasis started taking oral methotrexate 10 mg weekly without folic acid supplementation and developed a desquamating rash covering more than 70% of her body. Her rash developed within two weeks of starting methotrexate. She received treatment with calcium folinate and made a full recovery. Clinical images obtained on hospital day two show diffuse skin erosions and necrosis. Methotrexate-induced epidermal necrosis is an uncommon, potentially fatal, adverse reaction to methotrexate. Early diagnosis of methotrexate-induced epidermal necrosis can prompt early intervention with calcium folinate and hopefully mitigate potentially fatal outcomes associated with methotrexate toxicity.