Anaphylaxis in Children - Assessment and Referral After Emergency Treatment Guidelines

Publication: 01/10/2001  --
Last review: 30/01/2018  
Next review: 01/01/2021  
Clinical Guideline
ID: 60 
Approved By:  
Copyright© Leeds Teaching Hospitals NHS Trust 2018  


This Clinical Guideline is intended for use by healthcare professionals within Leeds unless otherwise stated.
For healthcare professionals in other trusts, please ensure that you consult relevant local and national guidance.

Anaphylaxis in Children: Assessment and Referral After Emergency Treatment Guidelines

Anaphylaxis Algorithm
Assessment (Clinical Signs)
  - Mild/Moderate Reaction
  - Severe Reaction
Further Management & Monitoring
Admission/Discharge Criteria
  - Discharge Checklist
Appendix 1 - Paediatric Allergy Record/Referral Form
Appendix 2 - Allergy Management Plan (EpiPen)

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1. Anaphylaxis is a severe, life-threatening, generalised or systemic hypersensitivity reaction characterised by sudden onset or rapid progression of symptoms with airway and/or breathing and/or circulatory symptoms [1, 2].

2. Acute allergic reactions result from the sudden systemic release of mediators from mast cells & basophils. Reactions tend commonly to be immunologically mediated ( IgE antibody), but non-immunological mechanisms (anaphylactoid) [e.g. non-steroidal anti-inflammatory agents & anaesthetics] can produce identical clinical features. IgE-mediated reactions are the subject of this guideline [3].

3. Allergic reactions may vary in severity. Urticaria and angioedema are the most common manifestations, but reactions with respiratory compromise or cardiovascular collapse may be life threatening. These serious reactions are also referred to as anaphylaxis [4]. Mild symptoms might progress rapidly unless given prompt medical treatment. Severe reactions are much easier to reverse if treatment is given early.

4. Most allergic deaths in children are the result of respiratory compromise. Hypotensive shock is rare outside of venom, or drug-induced reactions [5].

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1. For children in the community food allergies are the main triggers to allergic reactions. More than 90% of food-associated allergic reactions are caused by a short list of foods or food groups (Table 1), of which peanut & tree nuts are among the common causes of fatal reactions. Drugs (e.g., β-lactam antibiotics) & latex are the common triggers in the hospital setting [6].

Table 1 - Foods Associated With Allergic Reactions in Children

Cow’s Milk

Fish & Shellfish





Tree Nuts

Seeds (i.e. Sesame)

2. There are groups of patients who are at higher risk of severe allergic reactions (Table 2).

Table 2 - Risk Factors

Concurrent asthma

Intercurrent infection

Severe reaction / history of increasing reaction severity

Recent exercise or alcohol ingestion

Other - ongoing use of:
H1-antihistamines: may interfere with recognition of early symptoms
β-blockers: adrenaline less effective; risk of hypertension on adrenaline/epinephrine administration

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1. Signs & symptoms of an allergic reaction occur most commonly within minutes of exposure to a triggering allergen. Some reactions might develop more than 30 minutes after exposure and late-phase, or biphasic reactions, which occur 6-12 hours after the initial reaction have also been reported [6].

2. Biphasic allergic reactions are the recurrence of symptoms requiring treatment following complete resolution, and usually occur within 6-12 hours [7]. They are associated with severe reactions, whether triggered by foods or drugs. They occur rarely in the absence of initial airway compromise or hypotension.

3. Initial assessment should determine whether the history and physical findings are compatible with an allergic reaction. Reactions have varied clinical manifestations (Table 3). The majority of reactions include cutaneous signs. However, their absence would not preclude an allergic aetiology [6].

Table 3 - Clinical Manifestations

Mild Reaction

Severe Reaction

Itchy lips, mouth &/or throat


Erythema or urticarial rash

Stridor or voice change (laryngeal oedema)

Angioedema (swelling of lips/eyes/face)


Lump in throat (no voice change)

Severe abdominal pain


Sense of ‘impending doom’




Impaired consciousness

Abdominal pain

Cardiorespiratory arrest


4. Several conditions might cause an abrupt and dramatic patient collapse that could mimic anaphylaxis. Amongst children these other conditions include [4]:

  • Vasovagal (fainting) reactions
  • Panic attacks
  • Systemic mast cell disorders
  • C1 esterase deficiency syndromes (acquired & hereditary angioedema)
  • Foreign body aspiration
  • Acute poisoning
  • Hypoglycaemia

5. Special consideration should be given to the distinction between faints, panic & genuine anaphylaxis. Note - panic might complicate a mild allergic reaction [6].

  • Fainting reactions tend to cause pallor, weakness, nausea and vomiting.
  • Anaphylactic reactions characteristically tend to cause skin flushing, itch, urticaria & angioedema. Patients tend to be in a state of heightened awareness / anxiety.
  • Faints are associated with bradycardia & blood pressure is usually normal or increased.
  • In anaphylaxis, tachycardia is the most common rate disturbance. Bradycardia & hypotension are pre-arrest findings.
  • However, if in doubt, early use of adrenaline/epinephrine is indicated.

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1. Successful management of anaphylaxis depends on prompt recognition, appropriate and aggressive treatment of allergic symptoms.

2. Assess ABCDE (Airway, Breathing, Circulation, Disability, Exposure) and level of consciousness (an altered mental state might suggest hypoxia). The suggested management algorithm is outlined in the Anaphylaxis Algorithm [8, 9].

3. Remove the allergen, if possible. For example, remove the bee sting or stop the infusion of the drug or blood product.

4. Mild Reactions

If a reaction is clearly mild (Table 3) then the child may require oral antihistamine only. Mild reactions occurring in the community can be managed at home and therefore they do not need to be observed in hospital.

If reaction continues to progress and becomes more severe, the child should be observed, and reassessed as needed, in hospital for a period (see below).

5. Severe reactions

  • Maintenance of adequate oxygenation & administration of adrenaline/epinephrine are the priority.
  • All children should receive high flow oxygen.
  • If STRIDOR, then the child has laryngeal oedema. This should be treated with intramuscular [IM] adrenaline/epinephrine and nebulised adrenaline (Anaphylaxis Algorithm). Seek anaesthetic &/or paediatric intensive care assistance, as appropriate [4].
  • If WHEEZING, then the child has bronchoconstriction. This should be treated with intramuscular [IM] adrenaline/epinephrine (Anaphylaxis Algorithm). The guidelines for severe asthma may also be implemented. Seek anaesthetic &/or paediatric intensive care assistance, as appropriate [6].
  • Intramuscular adrenaline/epinephrine should be given into the anterolateral aspect of the middle third of the thigh. This gives rapid absorption and high peak plasma levels. The average time to maximum plasma adrenaline concentration using the intramuscular route is 8 minutes [7].
  • Doses of intramuscular adrenaline/epinephrine (1:1000) can be repeated every 5 minutes if the child is not improving [8]. If two doses of adrenaline/epinephrine are not sufficient, seek anaesthetic &/or paediatric intensive care assistance, as appropriate [6].
  • Children who are shocked should receive intravenous fluid as well as adrenaline/epinephrine. Large volumes may be needed as the increased vascular permeability in anaphylaxis can result in rapid transfer of 50% of the intravascular fluid into the extravascular space [6].
  • Anaphylaxis resistant to fluid resuscitation & IM adrenaline/epinephrine boluses may need an intravenous adrenaline infusion, and other therapy [6]. This requires paediatric intensive care management.

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1. All children should be monitored carefully once a reaction has been treated to ensure no deterioration in clinical response.

2. The duration and place of observation needs to be considered individually for each child’s circumstances.

  • Children who have had mild reactions, responding completely to treatment, should be observed for up to 2 hours before being discharged home.

    Extended observation for 6-12 hours to monitor development of possible late-phase reactions, should be considered for children who:
    • Live at a distance from an acute medical facility
    • Are returning home late at night (making it difficult for a parent to monitor the child)
    • Have had a reaction that included cardiorespiratory symptoms responding completely to treatment
    • Are asthmatic
    • Have had exposure to a large allergen dose (example, meal ingested completely without spontaneous vomiting)
    • Have a history of biphasic reactions previously

3. All children who have been treated for anaphylaxis or who have received adrenaline/epinephrine (nebulised or intramuscular) should be admitted to an inpatient ward for 6-12 hour observation [7].

4. All children discharged home should be warned about the possibility of late-phase reactions 6-12 hours later and advised to seek medical attention in that circumstance. They should be discharged with a supply of antihistamine (see Discharge Checklist) and advised to continue with regular doses over the next 24-48 hours [6].

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Serum tryptase levels. Tryptase is an enzyme released on mast cell degranulation. Levels peak 1-2 hours after the onset of anaphylaxis and can revert to baseline within 6-8 hours [8, 9]. The best time to measure serum tryptase is between 1- 2 hours (but no longer than 4 hours) after symptoms begin [8]. A serum (clotted) sample for tryptase measurement should be collected particularly when anaphylaxis is suspected (example, sudden onset acute severe wheeze) but no allergen can be identified. The sample may be stored overnight at 40C (fridge).

Consider taking blood sample if the anaphylaxis is venom-related, drug-related or idiopathic. Please indicate on referral form if the sample has been obtained.

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1. If a child is admitted with a suspected allergic reaction the ward medical teams should liaise with a member of the allergy team (see Discharge Checklist for contact details) with a view to arranging further in-patient and/or outpatient evaluation.

2. Children discharged from inpatient wards or the A&E department who require follow-up in allergy clinic include:

  • Infants under 1 year of age
  • Reactions that have included respiratory symptoms
  • Food allergy
  • Drug reactions
  • Insect sting allergy – NOT those with a large local skin reaction

3. For ALL children presenting with any probable allergic reaction complete the Paediatric Allergy Record/Referral Form’ (Appendix 1). Please indicate on the form if follow-up is required. This form should be forwarded to Dr Paediatric Allergy secretary - Leeds Children’s Hospital (LGI). Discuss any case where you are unsure of the need for follow-up with a member of the allergy team.

4. Children who have presented with anaphylaxis should bedischarged with self-injectable adrenaline/epinephrine (i.e. ‘EpiPen’) for future first-aid management of anaphylaxis (Table 2). These children should be discussed acutely with a member of the allergy team as self-injectable adrenaline/epinephrine should be prescribed in the context of a clear diagnosis and appropriate management plan. Family, and child where appropriate, should be instructed on when and how to use self-injectable adrenaline in future prior to discharge.

5. If a child is to be prescribed an adrenaline/epinephrine autoinjector, and the child is seen ‘out of hours’ or the Children’s Allergy Nurse Specialists are unavailable to deliver the training - please refer to Appendix 2 as a teaching tool.

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Record: 60

To provide evidence-based recommendations for appropriate diagnosis, investigation and management of anaphylaxis in children

To improve the diagnosis and management of anaphylaxis in children

Clinical condition:

Anaphylactic Shock

Target patient group: Children
Target professional group(s): Secondary Care Doctors
Secondary Care Nurses
Adapted from:

Evidence base

1. Simons FER, Ardusso LRF, Bilo B. et al. (2011). Worl Allergy Organisation Guidleines for the Assessment of management of Anaphylaxis. Journal of Allergy and Clinical Immunology. 2(3):13-36.

2. Royal College of Paediatrics and Child Health. Allergy care pathways for Children: Anaphylaxis (2011). (downloaded

3. Lieberman P., Kemp SF. & Oppenheimer J. et al. (2005). The diagnosis and management of anaphylaxis: An updated practice parameter. Journal of Allergy and Clinical Immunology. 115, pp.S483-523.

4. Sampson H.A., Munoz-Furlong A. & Campbell R.L. et al. (2006) Second symposium on the definition and management of anaphylaxis: summary report – Second National Institute of Allergy & Infectious Disease/Food Allergy and Anaphylaxis Network symposium. Journal of Allergy and Clinical Immunology. 117, pp.391-397.

5. Bock SA, Munoz-Furlong A, Sampson HA. (2001). Fatalities due to anaphylactic reactions to foods. Journal of Allergy and Clinical Immunology. 107, pp.191-193.

6. Vance, G. (2007). Management of acute allergic reaction in children. Clinical Governance Policies & Procedures. Newcastle Upon Tyne Hospitals NHS Foundation Trust. pp.1-10.

7. National Institute for Health and Care Excellence (NICE) clinical guideline. CG134. Anaphylaxis: assessment and referral after emergency treatment. 14 December 2011.

8. Tse, Y. & Rylance, G. (2009) Emergency management of anaphylaxis in children and young people: new guidance from the Resuscitation Council (UK). Archives of Disease in Childhood - Education and Practice Edition. 94, pp.97-101

9. Resuscitation Council (UK) (2008). Emergency treatment of anaphylactic reactions: Guidelines for healthcare providers. Working Group of the Resuscitation Council (UK). [Online at]

10. Fitzsimons R, van der Poel L-A, Thornhill W et al. (2015). Antihistamine use in children. Archives of Diseases in Childhood Education and Practice 100, 122-131.

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Document history

LHP version 1.0

Related information


LTHT Paediatric allergy record/referral form


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