Anaphylaxis recognition and treatment — Rapid

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.
Lie the patient flat with legs raised; if breathing is difficult allow a supported sitting position with legs extended, and never let them stand or walk.
Give high-concentration oxygen, monitor ECG, oxygen saturation and blood pressure, obtain intravenous access and use rapid crystalloid for hypotension.
Antihistamines do not treat airway or circulatory compromise and corticosteroids are not routinely advised for the initial emergency treatment.
Anaphylaxis recognition and treatment must be assessed by lesion duration, onset, distribution, symptoms, mucosal findings, systemic physiology and the full medicine timeline rather than by colour alone.
For Anaphylaxis recognition and treatment, document the working diagnosis, excluded emergencies, uncertain culprit or trigger, treatment response and the exact safety-net given.

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.

Airway compromise

Tongue swelling, difficulty swallowing, hoarse voice, stridor or rapidly progressive throat tightness indicates upper-airway threat.

Breathing compromise

Wheeze, hypoxia, increased work, exhaustion or silent chest after a sudden exposure indicates life-threatening lower-airway involvement.

Circulation compromise

Hypotension, collapse, confusion, clammy skin or cardiac arrest represents anaphylactic shock when onset and context fit.

Investigation priorities

Continuous physiological monitoringFirst step

Track response and detect deterioration during emergency treatment.

Management branches

Immediate ABC responseGive intramuscular adrenaline now

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.
After two appropriate doses with persistent ABC problems, escalate to experienced critical-care staff for refractory anaphylaxis and an intravenous adrenaline infusion.

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.Do not delay for venous access or antihistamine; avoid subcutaneous injection and inadvertent intravenous bolus, monitor closely, and escalate after two doses for infusion expertise.

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.Prescribe the strength appropriate to weight and device guidance, teach the exact brand, carry two devices, check expiry and storage, and do not use it as permission to delay emergency contact.

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