Authors: Diandra Aurora Zabala, Karen Lee Alabado, Maria Vinna Crisostomo, Michelle Sim


Introduction: Methotrexate is highly effective for psoriasis vulgaris and is often used as long-term management. Well known for its side effects of myelosuppression and liver toxicity, methotrexate also induces skin ulceration, which often heralds other markers of toxicity. We present a case of methotrexate toxicity in a patient treated with low-dose methotrexate.

Case Report: A 51-year old female was diagnosed with psoriasis and prescribed with methotrexate at 10mg/week. After two weeks, the patient complained of pruritus, which was treated with an antihistamine. On the fourth week of methotrexate, the patient noted improvement of psoriasis lesions, but, noted appearance of bullae and erosions on both lower extremities, associated with fever. The patient was admitted at a primary-care facility, was treated with intravenous hydrocortisone, and was subsequently transferred to our institution. Upon physical examination, the patient presented with multiple erosions and ulcers on extensor surfaces of the extremities, particularly on previous psoriasis lesions. She also had oral erosions and petechiae on her lower extremities. Laboratory examination showed pancytopenia, increased liver enzymes, bleeding parameters, and serum creatinine. The patient was then assessed as a case of methotrexate toxicity, and treated with intravenous folinic acid and supportive skin care. After 2 weeks, the oral and cutaneous lesions healed, along with improved complete blood count, bleeding parameters, liver enzymes and creatinine.

Conclusion: Methotrexate continues to be widely used in the treatment of plaque-type psoriasis. With this, a thorough work-up before and during therapy is crucial in order to avoid cutaneous and systemic side effects.





methotrexate toxicity, adverse drug reactions, psoriasis, methotrexate



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