Acute eosinophilic pneumonia related to a mesalazine suppository

It has been well known that mesalazine can cause the interstitial lung disease, such as Bronchiolitis obliterans with organizing pneumonia (BOOP), Non-Specific Interstitial Pneumonia (NSIP), or eosinophilic pneumonia. 5-Aminosalicylic acid (5-ASA), mesalazine, and sulfasalazine are important drugs for treating inflammatory bowel disease. Topical products of these limited systemic absorption and have less frequent side effects, therefore suppository form of these drugs have been used more than systemic drug. Most cases of measalzine-induced lung toxicity develop from systemic use of the drug. A 30-year-old woman had an interstitial lung disease after using mesalazine suppository because of ulcerative colitis. The lung biopsy demonstrated eosinophilic pneumonia combined with BOOP. She was recovered after stopping of mesalazine suppository and treatment with systemic steroid.