Delayed mammalian meat allergy (Alpha-Gal Syndrome) and hereditary angioedema in the differential diagnosis of irritable bowel syndrome

Irritable bowel syndrome with diarrhea, characterized by abdominal pain and loose or frequent bowel movements without organic disease, is a common condition worldwide. Alpha-gal syndrome, an increasingly recognized condition characterized by elevated alpha-gal immunoglobulin E (IgE) antibodies and improvement of symptoms on mammalian product-free diet, and hereditary angioedema, a hereditary condition that can cause recurrent abdominal pain and swelling and abnormal blood complement studies, can both mimic irritable bowel syndrome and be challenging to diagnose. In this review, we discuss the diagnosis, management, and pathophysiology of these two conditions.