Acute upper airway obstruction from acquired angioedema

C1 esterase inhibitor deficiency is an unusual cause of acute upper airway angioedema. This case of angioedema is secondary to acquired C1 esterase inhibitor deficiency associated with neoplastic disease and triggered by the use of angiotensin converting enzyme inhibitors. It was sufficiently severe to require emergency airway management. A guide to the evaluation and management of angioedema is presented.