Last Updated on by frcemuser


  • Acute allergic angioedema (90% of cases)
    • IgE mediated mast cell degranulation and histamine release as in urticaria
  • Non-allergic angioedema (bradykinin mediated)
    • Drug induced angioedema – ACE inhibitors
      • Suspect a non-allergic drug reaction if the person is taking an angiotensin-converting enzyme (ACE) inhibitor.
    • Hereditary angioedema (HAE)
      • Autosomal dominant genetic abnormality
      • C1-esterase-inhibitor deficiency or functional deficiency leading to the overproduction of bradykinin and a increase in vascular permeability
      • Suspect hereditary angioedema (HAE) if there is a history of one of the parents being affected
    • Acquired angioedema (AAE)
      • Acquired C1-esterase-inhibitor deficiency, usually secondary to lymphoma or connective tissue disorder e.g. SLE
  • Idiopathic angioedema
    • Usually a chronic and relapsing angioedema with an unknown cause
    • More common in people with autoimmune disorders, such as systemic lupus erythematosus (SLE) and autoimmune thyroiditis


Allergic Angioedema Non-Allergic Angioedema Anaphylaxis
  • Anatomically localised attack
  • Acute onset
  • Urticaria
  • Pruritus
  • Normotension
  • Anatomically localised attack
  • Gradual onset
  • No pruritus
  • Previous identical episodes
  • Abdominal pain
  • Normotension
  • Systemic symptoms
  • Rapid onset and progression
  • Respiratory failure
  • Cardiovascular collapse


Differential Diagnosis

  • Evolving anaphylaxis
  • Cellulitis
  • Erysipelas
  • Lymphoedema
  • SLE
  • Contact dermatitis

Management in ED

  • Rapidly developing angioedema Allergic angioedema without anaphylaxis: intravenous (IV) or intramuscular (IM) chlorphenamine and hydrocortisone
  • For people with stable angioedema: Offer a non-sedating antihistamine (such as cetirizine, fexofenadine, or loratadine) for up to 6 weeks (use clinical judgement to determine the duration of treatment).If symptoms are severe, give a short course of an oral corticosteroid
  • Hereditary Angioedema (suspect if there is a history of one of the parents being affected):
  • does not respond to treatment with adrenaline, antihistamines and corticosteroids. Attacks of HAE should be treated with Icatibant (a bradykinin B2 receptor antagonist) or C1 esterase inhibitor concentrate (if available)-fresh frozen plasma .

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