A Case of Severe Organ Dysfunction and Skin Lesions Due to Methotrexate Toxicity

Methotrexate is an anti-inflammatory and immunomodulatory drug, widely used for moderate to severe psoriasis and other rheumatological conditions such as rheumatoid arthritis, besides some types of malignancies. Side effects are more prevalent in high acute doses but can also be seen in low-dose chronic use, especially in cases of drug-dosing errors. Possible symptoms of toxicity include gastrointestinal, hepatic, hematologic and renal dysfunctions, but may also include mucositis and worsening of the psoriatic lesions. Here, we describe a case involving methotrexate toxicity in an elderly patient with psoriasis, detailing the management.