On this occasion, she presented with upper airway swelling secondary to angiotensin-converting enzyme inhibitor (ACEI)-induced angioedema, requiring endotracheal intubation. Initial management in the A&E department, under differential consideration for anaphylaxis and Ludwig’s angina, included oxygen via a non-rebreather mask (NRM), intramuscular adrenaline, intravenous dexamethasone, nebulization with Pulmicort, and antibiotic coverage with ceftriaxone and metronidazole. The gene discussed is ACE; the disease is angioedema.