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Pathology · single question

A patient receives local anesthetic and develops a rash and hives (urticaria) immediately. The MOST appropriate management is:

  1. Epinephrine (Type I IgE-mediated anaphylaxis — epi is first-line)
  2. Observe and monitor only
  3. Antihistamine only
  4. Corticosteroids (appropriate for Type IV delayed reaction 24-72h later)
Show answer and explanation

Correct answer: A. Epinephrine (Type I IgE-mediated anaphylaxis — epi is first-line)

  • A. Correct. An IMMEDIATE reaction to local anesthetic with rash, hives, and potentially bronchospasm/hypotension is a TYPE I IgE-MEDIATED ANAPHYLAXIS. EPINEPHRINE (intramuscular, thigh, 0.3-0.5mg of 1:1000) is the FIRST-LINE treatment — it reverses vasodilation, bronchospasm, and angioedema. Call 911. Antihistamines and corticosteroids are SECONDARY treatments.
  • B. Observation alone for anaphylaxis is inappropriate and dangerous.
  • C. Antihistamine alone is insufficient for anaphylaxis — it addresses histamine but not the life-threatening cardiovascular and respiratory effects.
  • D. Corticosteroids are appropriate for Type IV delayed hypersensitivity (contact dermatitis, occurring 24-72 hours later) — not for acute anaphylaxis.

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