[Two cases of drug-induced intrathoracic lesions caused by mesalazine in patients with ulcerative colitis].

We encountered 2 cases of drug-induced intrathoracic lesions caused by allergic reactions to mesalazine in patients with ulcerative colitis. Case 1: A 26-year-old man had a fever, cough and exertional dyspnea after 1 month of mesalazine treatment. He was hospitalized because of bilateral pulmonary infiltrates on a chest X-ray film. Case 2: A 27-year-old woman complained of fever and left back pain that exacerbated after 2 weeks of mesalazine treatment. She was hospitalized because of bilateral pulmonary effusions on chest CT. Both patients showed a positive reaction to a drug lymphocyte stimulation tests (DLST) for mesalazine. The first case was given a diagnosis of eosinophilic pneumonia by bronchoscopic examination, and responded to steroid therapy after discontinuation of mesalazine. The second case was given a diagnosis of pleuritis and improved on cessation of Mesalazine treatment.