Snapshot A 20-year-old girl presents to her primary care physician with abdominal pain, nonbloody diarrhea, and unexpected weight loss. On physical exam, she is noted to have aphthous stomatitis and perianal skin tags. She is referred to the gastroenterologists, where she underwent a colonoscopy showing non-contiguous cobblestone mucosa of the small intestine, along with a couple of ulcers. Histology reveals noncaseating granulomas. As she has a history of allergies to sulfa medications, she was not started on sulfasalazine. She is instead started on loperamide, an anti-diarrhea medication, as well as oral steroids with plans to transition to a biologic agent. Introduction Drugs sulfasalazine Mechanism of action activated by gut bacteria and metabolized into sulfapyridine and 5-aminosalicylic acid (5-ASA) 5-ASA anti-inflammatory inhibits leukotriene synthesis and lipoxygenase sulfapyridine anti-bacterial Clinical use inflammatory bowel disease ulcerative colitis Crohn disease juvenile rheumatoid arthritis Adverse effects gastrointestinal upset drug rash hemolytic anemia in those with G6PD deficiency malaise reversible oligospermia contraindications allergy to sulfa medicines porphyria