title: Angioedema in the emergency department: a practical guide to differential diagnosis and management.
abstract: BACKGROUND
  Angioedema is a common presentation in the emergency department (ED). Airway angioedema can be fatal; therefore, prompt diagnosis and correct treatment are vital.
  
  
  OBJECTIVE
  Based on the findings of two expert panels attended by international experts in angioedema and emergency medicine, this review aims to provide practical guidance on the diagnosis, differentiation, and management of histamine- and bradykinin-mediated angioedema in the ED.
  
  
  METHODS
  The most common pathophysiology underlying angioedema is mediated by histamine; however, ED staff must be alert for the less common bradykinin-mediated forms of angioedema. Crucially, bradykinin-mediated angioedema does not respond to the same treatment as histamine-mediated angioedema. Bradykinin-mediated angioedema can result from many causes, including hereditary defects in C1 esterase inhibitor (C1-INH), side effects of angiotensin-converting enzyme inhibitors (ACEis), or acquired deficiency in C1-INH. The increased use of ACEis in recent decades has resulted in more frequent encounters with ACEi-induced angioedema in the ED; however, surveys have shown that many ED staff may not know how to recognize or manage bradykinin-mediated angioedema, and hospitals may not have specific medications or protocols in place.
  
  
  CONCLUSIONS
  ED physicians must be aware of the different pathophysiologic pathways that lead to angioedema in order to efficiently and effectively manage these potentially fatal conditions.
authors.affiliation: Division of Immunology/Allergy, University of Cincinnati, 231 Albert Sabin Way, Cincinnati, OH, 45267, USA. jonathan.bernstein@uc.edu.
authors.forename: Jonathan A
authors.initials: JA
authors.lastname: Bernstein
authors.affiliation: Department of Emergency Medicine, E. O. Galliera Hospital, Genoa, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Cremonesi
authors.affiliation: Department of Oto-Rhino-Laryngology, Head and Neck Surgery, Ulm University Medical Center, Ulm, Germany.
authors.forename: Thomas K
authors.initials: TK
authors.lastname: Hoffmann
authors.affiliation: Department of Emergency Medicine, University Hospital, Aintree, Liverpool, UK.
authors.forename: John
authors.initials: J
authors.lastname: Hollingsworth
keywords: Angioedema; Bradykinin-mediated; Emergency department; Guideline; Histamine-mediated