Mesalazine-induced lung fibrosis.

The medical management of a patient with Crohn's disease should take into account the activity, site and behaviour of disease, and should be discussed with the patient, and 5-aminosalicylates are a group of medications which have been commonly used. Sulfasalazine is a combination of 5-aminosalicylic acid and sulfapyridine which acts only as a carrier to the colonic site of action but can still cause systemic side-effects including lung disease. In mesalazine the specific sulfapyridine-related side-effects, especially pulmonary reactions, are avoided. However, we present a case of lung fibrosis which was associated with mesalazine in a Crohn's patient.