Concurrent Sweet's syndrome and myopericarditis following mesalamine therapy

Mesalamine, or 5-aminosalicylic acid, is a frequently used medication for the treatment of inflammatory bowel disease (IBD). We report the case of a 40-year-old woman recently diagnosed with IBD and started on mesalamine, who presented with new onset tender skin lesions 3 days following medication administration. One day following the onset of skin lesions, the patient developed acute chest pain, shortness of breath, ECG changes, troponemia, C-reactive protein elevation and pericardial enhancement on cardiac MRI consistent with myopericarditis. Subsequent skin biopsy confirmed the diagnosis of Sweet's syndrome. On cessation of the drug, both the skin lesions and the cardiac symptoms resolved in combination with anti-inflammatory therapy. While mesalamine has been previously associated with myocarditis and pericarditis, to our knowledge this is the first case of coexisting Sweet's syndrome with myopericarditis in the context of mesalamine therapy.