Mesalazine-induced Hypersensitivity Pneumonitis

A 57-year-old woman with Crohn's disease (ulcerative proctitis) treated with mesalazine (5-ASA) developed worsening respiratory distress and cough. The lack of response to antibiotics and the results of bronchoalveolar lavage led to the diagnosis of mesalazine-related hypersensitivity pneumonitis, an infrequent entity. Symptoms improved after discontinuation of mesalazine and the administration of corticosteroid therapy. The authors discuss the diagnosis and management of this rare condition.

A diagnosis of mesalazine-related hypersensitivity pneumonitis should be considered when unexplained respiratory symptoms develop during treatment with mesalazine.It is important to distinguish pulmonary manifestations in patients with inflammatory bowel disease secondary to drug-related toxicity from the disease process itself.Amelioration of symptoms and improvement in imaging and lung function seem to occur only upon abrupt discontinuation of the drug; severe symptoms such as respiratory failure may justify corticosteroid therapy.