Multiple manifestations of methotrexate due to overdosing in chronic plaque psoriasis

Background: Methotrexate is the most commonly used immunosuppressive agent used in the treatment of psoriasis owing to its cytoprotective and immunomodulatory effects. However, it is generally safe at lower doses but a cumulative dose has been reported with toxicity manifestations such as Acute Kidney Injury, Bone marrow suppression and pancytopenia. Dermal toxicity is a rare manifestation of methotrexate probably due to overdosing or a result of pharmacological idiosyncrasy. Case description: A 56-year-old male presented to the dermatology department with complaints of fluid filled lesions on both limbs gradually progressing on face, ears, oral cavity and on whole body. The cutaneous lesions aggravated together with fever with chills, generalized body pains and pedal edema. Skin Biopsy and clinical evidence confirmed methotrexate as an offending drug and was immediately withdrawn and managed accordingly. Discussion and Evaluation: A Comprehensive clinical, laboratory, histopathogical examination Validated methotrexate induced toxicity. Causality and severity assessment revealed as probable on Naranjo scale and hartwig severity assessment scale assesed as Death. Conclusion: In this case patient erroneously took a cumulative dose of methotrexate thereby producing multiple toxicity manifestations Early identification and prompt withdrawal of the drug is crucial for impeding further serious morbidity.