Synopsis
Recognise anaphylaxis from rapidly evolving airway, breathing or circulation problems, deliver intramuscular adrenaline correctly, and organise risk-based observation and follow-up.
- Do not require skin signs: anaphylaxis can be diagnosed from sudden life-threatening airway, breathing or circulation compromise after a plausible exposure.
- Give adrenaline intramuscularly into the anterolateral thigh; the adult healthcare dose is 500 micrograms using 0.5 mL of 1 mg/mL solution.
- Repeat intramuscular adrenaline after five minutes if ABC problems persist and call expert help after two doses for refractory anaphylaxis management.
Key red flags
Hoarse voice, stridor, wheeze, hypoxia, hypotension, collapse, confusion, rapidly progressive tongue swelling or persistent symptoms after two adrenaline doses require immediate senior resuscitation support.
Tongue swelling, difficulty swallowing, hoarse voice, stridor or rapidly progressive throat tightness indicates upper-airway threat.
Investigation priorities
Track response and detect deterioration during emergency treatment.
Management branches
Sudden illness produces airway, breathing or circulation compromise with or without skin findings.
- Call emergency support, remove the trigger when feasible, position safely and give adult intramuscular adrenaline 500 micrograms into the anterolateral thigh.
- Provide high-concentration oxygen, continuous monitoring and rapid intravenous crystalloid for hypotension while repeating intramuscular adrenaline after five minutes if needed.
Key medicines
Adrenaline 1 mg/mL for intramuscular injectionAdults receive 500 micrograms intramuscularly, equivalent to 0.5 mL of 1 mg/mL solution, in the anterolateral thigh; repeat after five minutes if ABC problems persist.
Adrenaline auto-injector 300 microgramsAdults prescribed this device inject one 300 microgram dose into the outer thigh at anaphylaxis onset, call emergency services and use the second device after five minutes if not improving.