Angioedema 9/11/2018

Today Arthur presented a case of a young woman with a personal and family history of facial swelling presenting with acute onset periorbital and scalp swelling, in setting of recent hair-dye exposure. No urticaria or pruritus on presentation but she did have acute pruritus after exposure to the hair-dye. She responded quickly to benadryl and steroids. The final diagnosis is allergic angioedema.

What is angioedema? It is a non-pitting swelling of the deep/subcutaneous tissues.

Angioedema

(Image adapted to JAMA)

Pathophysiology of angioedema

  • Mast cell mediated (most common)
    • Examples: Food allergies, insect stings
    • IgE -> Mast Cells -> inflammatory response
      • BeE, FoodiE = IgE
    • Findings:
      • Flushing
      • Urticaria
      • Generalized pruritus
      • +/- bronchospasm, throat tightness, hypotension
    • Onset: Minutes after exposure, develop over the next few hours
    • Recovery: 24-48 hours
    • Anaphylaxis = life threatening systemic reaction which is a severe manifestation of an allergic reaction. Angioedema is a finding.
    • Management: IM Epi is FIRST LINE, 0.3 – 0.5mg IM, repeat Q5-15min PRN. Everything else (steroids, benadryl, anti-histamines) are adjuvant only. Get that IM Epi stat.
  • Bradykinin mediated
    • Examples: Acquired angioedema (AAE, associated with underlying malignancy or autoimmune conditions), RAAS-blocker angio edema (RAE, African Americans are 3x likely vs Whites), hereditary angioedema (HAE, autosomal dominant mode of inheritance)
    • Findings:
      • Absent urticaria/pruritus, bronchospasm.
      • Minimal skin findings but can have swelling without urticaria.
    • Onset: More prolonged course, can develop over 24-36 hours
    • Recovery: 2-4 days
    • Management: depends
  • Histamine/Unclear: Seen in idiopathic angioedema (IAE)

Angioedema algorithm

Capture

HAE Management

  • C1 Inh concentrate (takes a while to obtain)
  • Icatibant (synthetic bradykinin receptor antagonist)
  • Ecallantide (recombinant plasma kallikrein inhibitor)
  • FFP (fastest to get!)
  • Supportive care, airway monitoring

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