ABSTRACT
Leflunomide is a disease-modifying antirheumatic drug that has been available in Korea since 2003. Leflunomide induced interstitial pneumonitis has been reported as an adverse effect in other countries but not in Korea. A 57-year-old woman was treated with leflunomide since she had been resistant to methotrexate, hydroxychloroquine and sulfasalazine. She developed high fever, dyspnea, and non-productive cough 3 months after the administration of leflunomide. She was diagnosed leflunomide-induced interstitial pneumonitis based on history, physical, laboratory, radiologic and pathologic findings. The patient was treated by prednisolone 1 mg/kg/day with cholestyramine 24 g/day, resulting in dramatic improvement. Here we report a case of leflunomide induced pneumonitis treated successfully with high dose steroid.