OBJECTIVES: To understand the presentation and clinical course of angiotensin-converting enzyme (ACF) inhibitor-induced angioedema and to determine management factors associated with progression to airway compromise. STUDY DESIGN AND SETTING: Retrospective chart review of patients taking ACE inhibitors who presented to the emergency department with angioedema between December 1999 and July 2004 (n = 228). Clinical presentation, treatment, and clinical course were analyzed. RESULTS: The oral cavity was the most common location of upper-airway angioedema. Twenty-two (10%) patients required intubation, and all were intubated within 12 hours of presentation. Of the patients who required intubation, those who were started on an H-1-blocker were extubated earlier than those not on an H,blocker (P = 0.05). CONCLUSION: The locations of swelling and drooling on admission are predictive of the need for intubation. Other aspects of presentation, treatment, and disposition can help in management decisions for this potentially fatal condition. SIGNIFICANCE: This is the largest series to date of ACE inhibitor-related angioedema that challenges theories on the etiology and treatment of this condition. (c) 2007 American Academy of Otolaryngology-Head and Neck Surgery Foundation. All rights reserved.