Anaphylaxis

Any person, 4 weeks to 15 years, presenting with a multisystem allergic reaction characterised by an acute onset of cardiovascular or respiratory symptoms, usually associated with typical skin features and/or gastrointestinal symptoms.

Escalate immediately as per local CERS protocol.

History prompts, signs and symptoms

These are not exhaustive lists. Maintain an open mind and be aware of cognitive bias.

Red flags

Recognise: identify indicators of actual or potential clinical severity and risk of deterioration.

Respond: carefully consider alternative ECAT protocol. Escalate as per clinical reasoning and local CERS protocol, and continue treatment.

Clinical assessment and specified intervention (A to G)

If the patient has any Yellow or Red Zone observations or additional criteria (as per the relevant NSW Standard Emergency Observation Chart), refer and escalate as per local CERS protocol and continue treatment.

Position

Assessment	Intervention
General appearance/first impressions	Do not allow patient to sit up suddenly, stand, or walk Allow patient to adopt a safe position of comfort as tolerated. If hypotensive, elevate feet

Adrenaline dosing

Give adrenaline (epinephrine) 10 microg/kg (0.01 mL/kg of 1:1000) IM injection into lateral thigh. Maximum single dose 500 microg (0.5 mL of 1:1000). Patient's own auto-injector may be used to avoid delay, if trained. Repeat dose every 5 minutes as required.

Refer to table below for dosing if unable to obtain exact weight.

Age (years)	Weight (kg)	Volume (mL) of adrenaline 1:1000 ampoules
Up to 2	Up to 10	0.1 mL
2–3	15	0.15 mL
4–6	20	0.2 mL
7–10	30	0.3 mL
10–12	40	0.4 mL
12 and over	50 and over	0.5 mL

Airway

Assessment

Intervention

Patency of airway Signs of airway compromise: stridor hoarseness difficulty talking changes in voice or cry tongue or facial swelling

Maintain airway patency Consider airway opening manoeuvres and positioning Assist ventilation if clinically indicated Apply oxygen Apply continuous cardiorespiratory monitoring If airway compromise is present, give: nebulised adrenaline (epinephrine) 5 mg (equivalent to 5 mL or 5 ampoules of 1:1000) undiluted, with 8–10 L of oxygen via nebuliser. If symptoms remain, repeat once after 30 minutes Nebulised adrenaline (epinephrine) is not first-line therapy, but may be a useful adjunct to IM adrenaline (epinephrine), if upper airway obstruction is present

Breathing

Assessment	Intervention
Respiratory rate and work of breathing Auscultate chest (breath sounds) Oxygen saturation (SpO2)	To assist with breathing difficulties, keep patient supine at 45° – do not sit upright suddenly

Circulation

Assessment	Intervention
Perfusion (capillary refill, skin warmth and colour) Heart rate Blood pressure Cardiac rhythm	Assess circulation Attach cardiac monitor (consider defibrillator) Check blood pressure every 5 minutes until within normal limits (outside Yellow Zone and Red Zone criteria)
IVC and/or pathology	If persistent tachycardia and/or hypotension or poor response to treatment:  insert IV cannula, if trained If unable to obtain IV access, insert intraosseous, if trained See pathology section
Signs of shock: tachycardia and CRT 3 seconds and over and/or abnormal skin perfusion and/or hypotension	If signs of shock present, give sodium chloride 0.9% at 20 mL/kg IV/intraosseous bolus once only, maximum dose 1000 mL

Disability

Assessment	Intervention
AVPU	If AVPU shows reduced level of consciousness, continue to assess GCS, pupillary response and limb strength
GCS, pupillary response and limb strength	Obtain baseline and repeat assessment as clinically indicated
Pain	Assess pain. If indicated, give early analgesia as per analgesia section then resume A to G assessment

Exposure

Assessment	Intervention
Temperature	Measure temperature
Head-to-toe inspection, including posterior surfaces	Check and document any abnormalities Check for the presence of urticarial rash, erythema or skin flushing Consider giving antihistamine and comfort measures once stabilised

Fluids

Assessment	Intervention
Hydration status	Assess fluids, in and out. Document on fluid balance chart. Include gastrointestinal losses

Glucose

Assessment

Intervention

BGL

Measure BGL, where clinically relevant or of concern. See medication table for 40% glucose gel dosing If BGL between 2 mmol/L and 3 mmol/L and NOT symptomatic (Yellow Zone criteria): give 40% glucose gel buccal reassess BGL in 15–30 minutes until BGL over 3 mmol/L If BGL less than 2 mmol/L OR symptomatic (Red Zone Criteria) OR unable to tolerate oral glucose: give 40% glucose gel buccally in incremental doses, as tolerated, while establishing IV access escalate as per local CERS protocol

Focused assessment

• No specific focused assessment. Use clinical judgement and A to G assessment to determine focused assessment.

Precautions and notes

• Sitting upright suddenly or standing during anaphylaxis can be fatal.
• Most reactions occur within 30 minutes of exposure, but may be delayed several hours.
• Antihistamines have no role in treating or preventing respiratory or cardiovascular symptoms of anaphylaxis.
• Antihistamines primarily relieve cutaneous symptoms such as urticaria, itchiness and erythema.
• Patients with a history of acute hereditary angioedema (HAE) will not respond to adrenaline. Provide airway and breathing support and escalate as per local CERS protocol.
• Asthma and cardiovascular disease are associated with an increased risk of severe or fatal anaphylaxis.

Interventions and diagnostics

Specific treatment

• Do not allow patient with anaphylaxis to walk, sit up or stand suddenly. It can be fatal.
• Treat supine or on their side.

Airway compromise

If airway compromise is present, give:

nebulised adrenaline (epinephrine) 5 mg (equivalent to 5 mL or 5 ampoules of 1:1000) undiluted, with 8–10 L of oxygen via nebuliser. If symptoms remain, repeat once after 30 minutes.

Nebulised adrenaline (epinephrine) is not first-line therapy, but may be a useful adjunct to IM adrenaline (epinephrine), if upper airway obstruction is present.

Known asthma and/or wheeze

• Treat anaphylaxis first, including repeat doses of adrenaline.
• Able to breathe via spacer: give salbutamol by MDI via spacer, every 20 minutes for up to 3 doses, if required.
  • 1–6 years: 6 puffs (100 microg/puff)
  • 6 years and over: 12 puffs (100 microg/puff).
• Unable to breathe adequately via spacer: give nebulised salbutamol with 8–10 L of oxygen via nebuliser. Place nebule into nebuliser chamber and give every 20 minutes for up to 3 doses, if required.
  • 1–6 years: one 2.5 mg nebule
  • 6 years and over: one 5 mg nebule.
• If anaphylaxis has resolved but wheeze persists, consider wheeze (including viral-induced or suspected asthma) protocol

Urticarial rash

• For symptomatic treatment once haemodynamically stable, give antihistamine to alleviate itch:
  • 6 months–1 year: desloratadine 1 mg, orally once daily
  • 1–6 years: desloratadine 1.25 mg, orally once daily
  • 6–12 years: desloratadine 2.5 mg, orally once daily
  • 12 years and over: desloratadine 5 mg, orally once daily or if over 30 kg and can swallow tablets, loratadine 10 mg, orally once daily.
• Cool compress may be applied to rash to provide symptom relief.
• Avoid aspirin and NSAIDs.
• Avoid topical steroids. They do not alleviate symptoms or reduce the duration of rash.

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Analgesia

If pain score 1–6 (mild–moderate): give paracetamol 15 mg/kg orally once only, maximum dose 1000 mg

If severe pain present, give analgesia and escalate as per local CERS protocol.

Consider non-pharmacological pain relief (appendix).

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Nausea and/or vomiting

If nausea and/or vomiting is present and over 6 months give:

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Radiology

Not usually indicated. If there is concern for urgent radiology, escalate care as per local CERS protocol.

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Pathology

Not usually indicated. If there is concern for urgent pathology, escalate care as per local CERS protocol.

Medications

The patient’s weight is mandatory for calculating fluid and medication doses.

The Broselow Tape or APLS weight table (appendix) can be used only in circumstances where the patient cannot be weighed.

The shaded sections in this protocol are only to be used by registered nurses who have completed the required education.

Medications with contraindications or requiring dose adjustment are marked:

• ^H for patients with known hepatic impairment
• ^R for patients with known renal impairment.

Escalate to medical or nurse practitioner.

Evidence informed	Information was drawn from evidence-based guidelines and a review of latest available research. For more information, see the development process.
Collaboration	This protocol was developed by the ECAT Working Group, led by the Agency for Clinical Innovation. The group involved expert medical, nursing and allied health representatives from local health districts across NSW. Consensus was reached on all recommendations included within this protocol.
Currency	Due for review: Jan 2026. Based on a regular review cycle.
Feedback	Email ACI-ECIs@health.nsw.gov.au