Clinical Practice Guidelines

Anaphylaxis


  • Statewide logo

    This guideline has been adapted for statewide use with the support of the Victorian Paediatric Clinical Network

  • RCH: Consider 

    Criteria Led Discharge
    Acute Management
    Anaphylaxis action plans

    See also:

    Emergency drug and fluid calculator
    Resuscitation guidelines

    Anaphylaxis is a multi-systemic allergic reaction characterised by:

    1. At least one respiratory or cardiovascular feature and
    2. At least one gastrointestinal or skin feature.

    See also: For reactions which do not fulfill this definition, see  Urticaria guidelines

    Background to condition:

    Most reactions occur within 30 minutes of exposure to a trigger. Common causes of anaphylaxis in children include:

    • Foods (the most common cause) - Peanut, tree nuts, cow milk, eggs, soy, shell-fish, fish and wheat
    • Bites/stings - Bee, wasp, jumper ants
    • Medications- Beta-lactams, monoclonal antibodies (Infliximab) anaesthetics
    • Others - including exercise induced anaphylaxis, idiopathic anaphylaxis, and latex anaphylaxis, hydatid cyst rupture, biological fluid transfusion (e.g. blood, antivenom), food additives, etc.

    High-risk group of patients for anaphylaxis

    • History of anaphylaxis
    • Multiple allergy to food and drugs
    • Poorly controlled asthma
    • Pre-existing lung diseases

    Respiratory/chest features (Most common in children)

    • Tongue swelling
    • Stridor
    • Hoarse voice or change in character of the cry
    • Subjective feeling of swelling or tightness/tingling in the throat
    • Persistent cough
    • Wheeze
    • Dysphagia

    Cardiovascular features

    • Pale and floppy infant
    • Palpitations
    • Tachycardia
    • Bradycardia
    • Hypotension
    • Cardiac arrest
    • Altered consciousness/confusion

    Gastrointestinal features

    • Nausea
    • Vomiting
    • Diarrhoea
    • Abdominal/pelvic pain

    Mucocutaneous

    • Generalised pruritus
    • Urticaria/ intense erythema
    • Conjunctival erythema and tearing
    • Flushing
    • Angioedema
    • Neurological features
    • Headache (usually throbbing)
    • Dizziness
    • Confusion
    • Collapse with or without unconsciousness

    Investigations

    Anaphylaxis is a clinical diagnosis.

    Note: A raised mast cell tryptase may be a useful clue to the diagnosis of anaphylaxis but should only be ordered if the diagnosis is unclear, such as in unexplained and life-threatening cardiac or respiratory collapse. Serum tryptase returns to normal within hours of anaphylaxis, and a normal serum tryptase does not exclude anaphylaxis. Serial measurement (on arrival, 1 hour later and before discharge) may improve the sensitivity and specificity of diagnosis of anaphylaxis. Serum tryptase is unstable and must be transported to the laboratory quickly.

    Acute Management:

    Flow diagram

    • Posture: treat the patient in supine position, or left lateral position for vomiting patient (or sitting at 45 degrees if breathing is difficult Legs should be elevated in the setting of hypotension. Do not stand.
    • Intra-muscular adrenaline 0.01ml/kg of 1/1000 (maximum 0.5ml), into lateral thigh which should be repeated after 5 minutes if patient not improving.
    • Do not use subcutaneous adrenaline, as absorption is less reliable than the intramuscular route.
    • Do not use IV bolus adrenaline unless cardiac arrest is imminent.

    The following doses of adrenaline may be used if the weight is unknown:

     IM dose of 1:1000 adrenaline  (repeat after 5 min if no better)
     Adult  500 micrograms IM (0.5 mL)
     Child more than 12 years  500 micrograms IM (0.5 mL)
     Child 6 - 12 years  300 micrograms IM (0.3 mL)
     Child less than 6 years  150 micrograms IM (0.15 mL)

    • If patient is not improving after repeated doses of IM adrenaline, consult senior staff (e.g. ICU/anaesthetics) and consider adrenaline infusion (0.05 - 1 mcg/kg/min).
    • In addition to adrenaline, resuscitate with fluid; repeated boluses of 20 ml/kg of 0.9% saline may be required for shock.
    • Nebulised adrenaline is not recommended as first-line therapy, but may be a useful adjunct to IM adrenaline if upper airway obstruction is present.
    • If airway oedema is not responding to parenteral and nebulised adrenaline, early intubation is indicated.
    • Corticosteroids, antihistamines and antileukotrienes have no proven immediate benefit on life threatening anaphylaxis. They may improve mild cutaneous symptoms.

    Other therapies to consider

    • Nebulised salbutamol is recommended if the patient has respiratory distress with wheezing or consider other anti asthma medications.
    • Antihistamines may be given for symptomatic relief of pruritus. Second generation antihistamines are preferred (promethazine can cause hypotension).
    • Corticosteroids may be considered at the discretion of the treating physician, especially for bronchospasm, although the limited evidence available does not support their use.

    Admission

    All children with anaphylaxis should be observed for at least 4 hours. Admission should be considered if any of the following circumstances apply:

    • Greater than one dose of adrenaline (including nebulised adrenaline) required.
    • A fluid bolus required.
    • Inadequate response to treatment.
    • The child lives a long distance from medical services.

    If the patient is considered to be at continuing risk of anaphylaxis in the community, they should be discharged with:

    • Anaphylaxis action plans
    • EpiPen/EpiPen Jnr®, and trained in its correct use with an Epipen trainer. Current dose recommendations are:   <20 kg = EpiPen Jnr® (150 µg) and > 20 kg = EpiPen® (300 µg). EpiPen®/EpiPen Jnr® are available on PBS for all patients with a history of acute anaphylaxis.  See Guidelines for the prescription of an EpiPen for more information.
    • Epipen requires authority prescription or can be purchased without a prescription at full cost.  See PBS authority indications.
    • Consider provision of a Medicalert bracelet .
    • Most children with anaphylaxis should be referred to a paediatric allergy specialist.
    • Ensure that asthma control is addressed.

    Consider consultation with local paediatric team:

    • All children requiring more than one dose of adrenaline.
    • Paediatric/allergy follow-up for all children who present with anaphylaxis.

    When to consider transfer to tertiary centre:

    • Inadequate adrenaline response.
    • Multiple doses of adrenaline.
    • Adrenaline infusion.
    • Immediate life-threatening situations.
    • Child requiring care beyond the comfort level of the hospital.

      For emergency advice and paediatric or neonatal ICU transfers, call the Paediatric Infant Perinatal Emergency Retrieval (PIPER) Service: 1300 137 650. 

     Information specific to RCH

    Notify ICU if >2 adrenaline boluses required

    • Outpatient follow up with allergy/immunology recommended (not earlier than 6 weeks because false negative skin prick testing can occur)
    • Epipen trainers are available from the Immunology Department or the Short Stay Unit 
    • Consider placing an  alert on the Emergency Department System if at risk of in-hospital anaphylaxis

    Other resources:

    Peanut and tree nut allergy Parent Information Sheet

    Links for further reading:  www.allergy.org.au/

    Last updated
    November 2015