Anaphylactic reaction to the first dose of subcutaneous methotrexate in JIA: a case report and literature review

Results A 13-years old adolescent girl diagnosed with polyarticular JIA (RF +/ANA-/HLA-B27-) received the first dose of subcutaneous methotrexate in our Day Care centre due to refractoriness to NSAIDs. While she was leaving the building after 10 minutes of medication she developed urticaria, angioedema, shortness of breath and hypoxia (O2 saturation of 85%). After administration of 0.5ml of 1:1000 adrenaline, 500ml of saline, 2.5mg of dexchlorpheniramine and 125mg of methylprednisolone she recovered and was discharged home after a short period of stay. The methotrexate she used was also for intrathecal administration and had only distilled water as suspension. Conclusion This is the first case report of anaphylaxis to methotrexate in a patient with JIA without previous exposure. Considering it is a very rare and fatal reaction, we suggest that the first subcutaneous dose should be administrated in a health center and the patient should wait 30 minutes before leave.