Anaphylaxis

Emergency Medicine

Severe systemic hypersensitivity — sudden onset + airway/breathing/circulation compromise ± skin/mucosal changes.

Causes

  • Food (nuts, seafood)
  • Drugs (β-lactams, NSAIDs, contrast, muscle relaxants)
  • Insect stings
  • Latex, idiopathic

Clinical features

  • Urticaria, angio-oedema, wheeze, stridor, hypotension, GI symptoms

Management

  • Adrenaline 0.5 mg IM (anterolateral thigh) — repeat q5 min
  • Remove trigger, high-flow O₂, lie flat with legs raised
  • IV crystalloid 500-1000 mL fast
  • Second-line: chlorphenamine 10 mg IV, hydrocortisone 200 mg IV, salbutamol/ipratropium neb
  • Refractory: adrenaline infusion 0.05-1 mcg/kg/min, glucagon if on β-blocker

Follow-up

  • Observe ≥6 h (biphasic risk); adrenaline auto-injector × 2, action plan, allergist referral
  • Tryptase at 1-2 h and 24 h

References

  • Resus Council 2021 Anaphylaxis

Related in WardRound

Educational — verify locally.

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