Mesalazine-induced organizing pneumonia in a patient with ulcerative colitis: a case report

Mesalazine is a key drug in the treatment of ulcerative colitis. We report the case of a 29-year-old woman with mesalazine-related organizing pneumonia. She was diagnosed with ulcerative colitis and was started on oral mesalazine. Fifty days after administration, a high fever was observed. Additionally, the laboratory data and imaging findings suggested organizing pneumonia. After discontinuation of mesalazine, the body temperature rapidly decreased, and lung infiltration improved. Furthermore, we reviewed the previous literature on mesalazine-mediated lung diseases.