Idiopathic Intestinal Angioedema: A Diagnostic Dilemma

Angioedema is an allergic reaction that usually involves the face and pharynx. Intestinal angioedema is a rare subtype that is typically linked to the use of angiotensin-converting enzymes inhibitors (ACEIs). Intestinal angioedema is challenging to diagnose, as it can mimic gastroenteritis or other inflammatory bowel conditions. Herein, we present a 34-year-old female who presented with recurrent episodes of abdominal pain. She underwent extensive workup for her abdominal pain and rash, and all was unrevealing except for high Immunoglobulin E (Ig E). Multiple imaging came back negative for any pathology. The allergy and immunology team evaluated the patient, and they believed her symptoms are likely caused by isolated intestinal angioedema with a histamine-related rash. She was started on high doses of antihistamines; her symptoms partially improved. Subsequently, she was started on a trial of omalizumab, which resulted in complete resolution of her symptoms. In conclusion, intestinal angioedema is a rare disease that should be suspected in cases of recurrent abdominal pain with negative workup, especially if the patient is taking ACEIs. Few cases were reported in the literature for patients on ACEI. In our case, the diagnosis was a challenge, as the patient was never on ACEI.