Vancouver IM LMR

Thank you to Dr. Ryan Lo (Allergy & Immunology) for giving a comprehensive yet practical talk on the approach to urticaria and angioedema, which I think often remains a black box for internal medicine residents! This was a really useful noon rounds for our learners and staff.

See the didactic slide deck here.

Key takeaways:

• Approach to urticaria:
  • lesions lasting < 48h AND < 6 weeks in duration
    • Spontaneous
    • Infectious
    • Allergic (triggered by food/ venom/ latex/ medications/ contact)
      • NO routine diagnostic tests are recommended if it is clearly allergic!
  • lesions lasting < 48h AND > 6 weeks in duration i.e. chronic urticaria!
    • Chronic spontaneous urticaria (CSU)
      • Routine investigations: CBC + diff, CRP, IgG anti TPO and total IgE
    • Chronic inducible urticaria
      • E.g. symptomatic dermographism, cold urticaria, delayed pressure urticaria, etc
    • Other
  • lesions lasting > 48h
    • Urticarial vasculitis
• Approach to angioedema:
  • Angioedema with urticaria (mast cell/ histamine pathway) → go down urticaria pathway
  • Angioedema without urticaria (kinin pathway)
    • ↓ C4, ↓C1-INH level, ↓C1-INH function
      • Hereditary angioedema type I
      • Acquired angioedema
    • ↓ C4, normal C1-INH level, ↓C1-INH function
      • Hereditary angioedema type II
    • Normal C4, normal C1-INH level & function
      • Hereditary angioedema with normal C1-INH
      • Drug induced (e.g. ACEi, NSAID, DPP4i, neprilysin-inhibitor)
      • Idiopathic