Sulfasalazine-induced immune thrombocytopenia.

Sulfasalazine is a well established disease-modifying anti-rheumatic drug commonly used in the treatment of rheumatic disorders and inflammatory bowel disease. Sulfasalazine was generally well tolerated in clinical trials, the most frequently reported adverse effects being adverse gastrointestinal effects, headache, dizziness and rash; myelosuppression can also occur. We are now reporting the first case of autoimmune thrombocytosis following sulfasalazine treatment.