Methotrexate Toxicity During Treatment of Chronic Plaque Psoriasis: A Case Report and Review of the Literature

Methotrexate continues to be one of the most widely used systemic immunosuppressive agents in dermatology. In addition to the important, well-characterized adverse effects such as hepatotoxicity and myelosuppression, methotrexate may induce a number of rare cutaneous adverse events including methotrexate-induced ulceration. We present a case of methotrexate-induced cutaneous ulceration in a patient with chronic plaque psoriasis occurring during long-standing methotrexate therapy. Withdrawal of the drug and appropriate skin care led to rapid healing of the ulceration and the agent was later safely reintroduced for the ongoing management of the patient's chronic plaque psoriasis. Review of the literature demonstrates cases of this important rare adverse event, primarily occurring in patients with chronic plaque psoriasis, induced by triggers such as accidental overdose or introduction of an interacting agent. Cutaneous ulceration typically precedes other markers of toxicity. Active treatment with folinic acid (calcium leucovorin) may be required. Early recognition, prompt cessation of methotrexate, and appropriate treatment minimizes morbidity. Dermatologists need to be alert to the possibility of cutaneous adverse events associated with methotrexate therapy, aware of potential drug interactions, and confident in the management of methotrexate toxicity.