Snapshot A 23-year-old woman with past medical history of multiple allergies leading to facial swelling presents with marked difficulty breathing, abdominal pain, and swelling of the face and neck. On physical exam, her extremities are also noted to be markedly swollen (picture). She is immediately sedated for intubation to maintain patency of airway. Chart review reveals newly-started ACE-inhibitor. She is given epinephrine, fluids, and fresh frozen plasma. Introduction Disorder of complement, causing angioedema Genetics login to view 1 more bullet Pathogenesis login to view 10 more bullets Epidemiology login to view 1 more bullet Risk factors login to view 3 more bullets Presentation Symptoms/physical exam login to view 12 more bullets Evaluation Best initial test login to view 2 more bullets To confirm diagnosis if ↓ C4 login to view 2 more bullets Differential Diagnosis Anaphylaxis Allergic angioedema Facial cellulitis SVC syndrome Treatment Anaphylaxis presents very similarly to angioedema and often cannot be differentiated immediately in an emergency room setting login to view 4 more bullets Assess airway, even after administering treatment login to view 1 more bullet As soon as possible, especially if epinephrine and anti-histamines are not effective, administer medications for hereditary angioedema login to view 3 more bullets Prognosis, Prevention, and Complications Prognosis login to view 2 more bullets Complications login to view 3 more bullets