Anaphylactic Shock Following Multiple Self-Medication Exposures in a Patient With Rheumatoid Arthritis Receiving Methotrexate: A Case Report.

We report a 51-year-old female with rheumatoid arthritis (RA) on long-term methotrexate, hydroxychloroquine, and sulfasalazine, who self-administered multiple medications, including diclofenac 50 mg, without medical supervision. She presented with acute-onset shortness of breath, generalized pruritus, angioedema, and palpitations, and was found to be in severe anaphylaxis with cardiovascular collapse, with a blood pressure of 60/nil mmHg and a heart rate of 143 beats per minute. Diclofenac was considered the most likely trigger based on temporal association and known nonsteroidal anti-inflammatory drug (NSAID) hypersensitivity risk; however, causality cannot be definitively proven as several medications were taken within the same exposure window. Investigations revealed leukocytosis, microcytic anemia, reactive thrombocytosis, and elevated alkaline phosphatase. The electrocardiogram showed no ischemic ST-segment changes or conduction abnormalities. Prompt resuscitation with intramuscular epinephrine resulted in hemodynamic stabilization within 15 minutes of the first dose, with complete angioedema resolution within 30 minutes. The patient was managed without intensive care unit admission and discharged in stable condition on day three. This case highlights the diagnostic and management challenges of severe hypersensitivity reactions occurring in the setting of polypharmacy and emphasizes the importance of individualized analgesic planning and careful medication counseling in patients with RA receiving chronic therapy.