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.

(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

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