Anaphylaxis
Disclaimer
These guidelines have been produced to guide clinical decision making for the medical, nursing and allied health staff of Perth Children’s Hospital. They are not strict protocols, and they do not replace the judgement of a senior clinician. Clinical common-sense should be applied at all times. These clinical guidelines should never be relied on as a substitute for proper assessment with respect to the particular circumstances of each case and the needs of each patient. Clinicians should also consider the local skill level available and their local area policies before following any guideline.
Read the full CAHS clinical disclaimer.
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Aim
To guide PCH ED staff with the assessment and management of anaphylaxis presenting to the Emergency Department.
Background1
Anaphylaxis is an Immunoglobulin E (IgE) mediated potentially life‐threatening severe allergic reaction, which may progress to shock and severe airway compromise.
The most common causes of anaphylaxis in children include:
- Foods: Peanut, tree nut, egg, cow’s milk, soy, wheat, sesame seeds, fish and seafood.
- Insect stings and bites: Bees, wasps, hornets, jack jumper ants, fire ants.
- Latex
- Drugs: Penicillin, Non-Steroidal Anti-Inflammatory Drugs (NSAIDs), aspirin, anaesthetic agents, radiographic contrast media.
- Exercise, also in combination with certain foods, heat, cold, pressure.
Anaphylaxis flowchart
Risk factors
Assessment
- Asthma: asthmatics are more likely to have more severe respiratory problems during anaphylaxis.
- The severity of past allergic reactions does not reliably predict the severity of future reactions.
- Anaphylaxis can occur without skin symptoms.
- Touching or smelling the allergen may cause mild/moderate reaction but is unlikely to cause anaphylaxis.
Examination
Symptoms of allergic reaction are categorised as mild, moderate or as anaphylaxis (= severe):
Clinical features
Mild to moderate allergic reaction
- swelling of the lips, face, eyes
- tingling of the mouth
- hives or welts
- abdominal pain (abdominal pain and vomiting can be a sign of anaphylaxis in insect sting/bite allergy)
- vomiting.
Anaphylaxis (only one feature may present)
- swelling/tightness in the throat
- swelling of the tongue
- difficulty speaking/hoarse voice
- difficulty breathing/stridor
- wheeze or persistent cough
- persistent dizziness
- collapse
- pallor, floppiness or drowsiness (in very young children)
- abdominal pain and vomiting – insect sting/bite allergy only.
Management
- Ensure allergen is removed
- Lay the patient flat
- if there is respiratory distress then the patient can sit upright.
- Do not allow the patient to stand or walk. Refer to the Anaphylaxis Flowchart.
- Assess airway, breathing, circulation, disability and exposure (ABCDE)
- Administer high flow oxygen
- Record a full set of observations on the Observation and Response Tool and the Clinical Comments Chart
- Full neurological observations (FNO) as clinically indicated
- Document chest auscultation and perfusion.
- Document and report presence of urticarial rash, itching of eyes, lips, mouth or throat, facial swelling, tongue swelling, difficulty breathing, stridor, wheeze, coughing, chest tightness, circulatory shock (i.e. sluggish capillary refill, tachycardia, hypotension, weak pulses), abdominal pain, nausea and vomiting.
- Report severe irritability and drowsiness in very young children.
Initial management in all patients with acute signs of anaphylaxis
- Immediately administer intramuscular (IM) adrenaline (epinephrine) monograph - PCH Medication Manual (internal WA Health only) (epinephrine) 1:1000 strength (= 1 mg/mL)3
- Dose: All ages: 10 microg/kg
- Maximum dose: 500 microg
- Note: antihistamines are not indicated in the treatment of anaphylaxis
- Continuous cardiac monitoring and pulse oximetry
- Document pulse, respirations, blood pressure and oxygen saturations 15 to 30 minutely until stable
- Observe closely and report worsening symptoms
- Administer 2nd dose of IM adrenaline (epinephrine) if ongoing symptoms of anaphylaxis 5 minutes after 1st dose.
Adjunct management
Signs of shock
- Insert two large intravenous (IV) cannulae and give a 20mL/kg sodium chloride 0.9% bolus. Assess response and repeat as necessary
- Commence an adrenaline (epinephrine) (internal WA Health only) infusion if the patient remains hypotensive after 40mL/kg of sodium chloride 0.9%
- Paediatric Critical Care (PCC) referral.
Signs of upper airway obstruction
- Nebulised adrenaline (epinephrine) (internal WA Health only) 1:1000 (1mg/mL) ampoule:
- Give 0.5mg/kg/dose (0.5mL/kg/dose) to a maximum of 5mL undiluted. Smaller doses can be made up to a volume of 5mL with sodium chloride 0.9%.9
- Consider need for intubation and prepare equipment
- Consider adrenaline (epinephrine) infusion and refer to PCC
- Continuous cardiac monitoring, pulse oximetry
- Document: pulse, respirations, blood pressure and oxygen saturations 5 to 15 minutely until stable
- Observe closely and report worsening symptoms.
Persistent wheeze
- Give salbutamol metered dose inhaler (MDI) via spacer3,5
- < 6 years: 6 puffs
- ≥ 6 years: 12 puffs
- Consider repeating the IM adrenaline (epinephrine) dose
- Consider adrenaline (epinephrine) infusion
- Refer to PCC
Disposition
- All patients who have received IM adrenaline (epinephrine) must be observed for minimum 4 hours after last dose of adrenaline
- Do not allow the patient to stand or walk until they are haemodynamically stable, which is usually a minimum of 1 hour after 1 dose of adrenaline and 4 hours if more than 1 dose of adrenaline has been administered.10
- Admit to Emergency Department Short Stay Unit (ESSU) or inpatient ward
- Have a low threshold to admit overnight if patient presents in the late evening
- Admit to PCC if adrenaline infusion is required.
Discharge
- Prescribe (requires Pharmaceutical Benefits Scheme authority), and supply (after hours) or PCH pharmacy to dispense (during pharmacy opening hours), two adrenaline (epinephrine) devices.
- Two brands of AAI are currently available in Australia:
- EpiPen® 150 microg and 300 microg
- Anapen® 500 microg
In patients with known anaphylaxis, prescribe the same brand of AAI which they have used previously (except when patients have grown and are switching from EpiPen® 300 microgram to Anapen® 500 microgram).
ASCIA Adrenaline (epinephrine) Injector Dose Recommendations2
| 7.5 to 20 kg |
N/A |
EpiPen® Junior (150 microg) |
| >20 kg to 50 kg |
N/A |
EpiPen® (300 microg) |
| >50 kg |
Anapen® 500 (500 microg) |
N/A |
- Provide education and anaphylaxis action plan for relevant adrenaline device.
- Ensure patient has follow up with immunology / allergy specialist.
Information for Parents and Carers1
Information on where to access resources:
References
- ASCIA website. Available from: https://www.allergy.org.au/
- ASCIA Adrenaline Injector Dose Recommendations – ASCIA Website Cited September 2025. Available from: ASCIA Guidelines for adrenaline injector prescription - Australasian Society of Clinical Immunology and Allergy (ASCIA)
- Updated anaphylaxis guidelines: management in infants and children 2021, Australian Prescriber Vol44.3 June 2021. Cited September 2025. Available from: Updated anaphylaxis guidelines: management in infants and children (nps.org.au)
- Australian Injectable Drugs Handbook (AIDH) – 9th Edition 2025 Collingwood Victoria, Society of Hospital Pharmacists of Australia
- ASCIA Guidelines - Acute Management of Anaphylaxis. Updated 2024. Cited 16 November 2024. Available from: https://allergy.org.au/images/ASCIA_HP_Guidelines_Acute_Management_Anaphylaxis_2024.pdf
- Epinephrine (adrenaline) (oral inhalation): Pediatric drug information – UpToDate Cited: September 2025. Available from: Epinephrine (adrenaline) (oral inhalation): Pediatric drug information - UpToDate (health.wa.gov.au)
- difficulty breathing
- tongue swelling
- difficulty breathing
- tongue swelling
| Reviewer/Team: |
ED HOD, ED Consultants, ED CNM, ED CNS, Pharmacy, CNC Immunology, CNM DTU
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Last reviewed: |
Sep 2025 |
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Next review date: |
Sep 2028 |
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