• adolescent
• abdominal pain
• angioedema

A 15-year-old girl was admitted with acute crampy abdominal pain and repeated vomiting over the preceding 2 hours; no fever, diarrhoea or abdominal trauma was reported. She had started oestrogen–progestin contraception 3 months ago. She had sought medical advice twice in the previous weeks for self-limiting episodes of right hand swelling, without urticaria. On examination, she was unwell and in pain, with severe tenderness in the right lower quadrant, without guarding or rebound tenderness. Bowel sounds were diminished. Blood tests were unremarkable. Two hours after admission, an abdominal ultrasound scanning showed an impressive wall thickening (>1 cm) of the terminal ileum, caecum and ascending colon (figure 1). Abundant free intraperitoneal fluids in the pelvis and in the hepatorenal recess were present.