Snapshot A 15-year-old boy is rushed to the emergency department by his mother due to increased difficulty with breathing. His mother says that he does not have a food allergy and that this has happened to him before after undergoing a dental procedure. She reports that in the father's side of the family, they suffer from these episodes of swelling but usually self resolve. On physical exam, the patient has swelling of the lips, tongue, and skin around the face and arms. He is immediately sedated and subsequently intubated and treated for anaphylaxis which does not improve his symptoms. Laboratory testing is significant for decreased C4 and C1 inhibitor levels as well as normal C1q levels. Introduction Clinical definition login to view 10 more bullets Genetics login to view 2 more bullets Associated conditions login to view 1 more bullet Prognosis login to view 3 more bullets Epidemiology Incidence login to view 1 more bullet Demographics login to view 1 more bullet Location login to view 1 more bullet Risk factors login to view 1 more bullet ETIOLOGY Pathophysiology login to view 6 more bullets Presentation Symptoms login to view 13 more bullets Physical exam login to view 10 more bullets Studies Labs login to view 5 more bullets Differential Drug-induced anaphylaxis Contact dermatitis Atopic dermatitis Superior vena cava syndrome Treatment Conservative login to view 5 more bullets Medical login to view 12 more bullets Complications Asphyxiation can result in death ≥ 30% mortality in patients with laryngeal angioedema login to view 1 more bullet