Anaphylaxis in Children: Assessment and referral after emergency treatment guidelines

1. Background
2. Causes
3. Assessment
4. Other diagnoses
5. Treatment
6. Further management
7. Investigations
8. Discharge

Appendix 1 - Paediatric Allergy Record/Referral Form 

Anaphylaxis Guidelines

Back to top

1. BACKGROUND

1.1 Anaphylaxis is a serious systemic hypersensitivity reaction that is usually rapid in onset and may cause death. Severe anaphylaxis is characterised by potentially life-threatening compromise in airway, breathing and/or the circulation and may occur without typical skin features or circulatory shock being present [2].

1.2 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].

1.3 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.

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

Back to top

2. CAUSES

2.1 For children in the community, food allergies are the main triggers to allergic reactions [6]. 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 [7].

Table 1 - Foods Associated With Allergic Reactions in Children

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

Table 2 - Risk Factors [2]

Back to top

3. ASSESSMENT

3.1 Signs & symptoms of an allergic reaction occur most commonly within minutes of exposure to a triggering allergen. Some reactions might develop up to two hours after exposure (e.g. drug allergy).

3.2 Biphasic allergic reactions are the recurrence of symptoms requiring treatment following complete resolution, and usually occur within 6-12 hours [2, 8]. They are associated with severe reactions, whether triggered by foods or drugs. They occur rarely in the absence of initial airway compromise or hypotension.

3.3 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 manifest with skin signs. However, skin signs (i.e. urticaria) are absent in 10-20% of anaphylactic reactions, which can cause delay in the recognition of anaphylaxis [2].

Table 3 - Clinical Manifestations of Allergic reaction

Back to top

4. OTHER POSSIBLE DIAGNOSES

4.1 Several conditions might mimic anaphylaxis. Amongst children these other conditions include [4]:

• Acute asthma
• Acute generalised urticaria
• Non-allergic angioedema
• Scromboid food poisoning (fish)
• Vocal cord dysfuction (inducible laryngeal obstruction)
• Systemic mast cell disorders
• C1 esterase deficiency syndromes (acquired & hereditary angioedema)
• Foreign body aspiration
• Acute poisoning
• Hypoglycaemia
• Vasovagal (fainting) reactions
• Panic attacks

4.2 Special consideration should be given to the distinction between faints, panic & genuine anaphylaxis. Note - panic might complicate a mild allergic reaction [7].

• 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.

Back to top

5. TREATMENT

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

5.2 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 [1,9].

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

5.4 MILD/ MODERATE REACTIONS - if a reaction is clearly mild / moderate (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.

Oral Antihistamine [10]
Under 2 years of age: Chlorphenamine 1mg (2.5mls)
2 - 6 years of age - Cetirizine 5mg (5mls)
Over 6 years of age - Cetirizine 10mg (10 mls)

Oral Steroids - the use of oral steroids for the treatment of mild/moderate allergic reactions is not clinically indicated [2].

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

5.6 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 [7].

• 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 [8].

• Doses of intramuscular adrenaline/epinephrine (1:1000) can be repeated every 5 minutes if the child is not improving [9]. If two doses of adrenaline/epinephrine are not sufficient, seek anaesthetic &/or paediatric intensive care assistance, as appropriate [7].

• 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 [7].

• Anaphylaxis resistant to fluid resuscitation & IM adrenaline/epinephrine boluses may need an intravenous adrenaline infusion, and other therapy [7]. This requires paediatric intensive care management.

Back to top

6. FURTHER MANAGEMENT

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

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

• Children who have had mild / moderate reactions, responding completely to treatment, should be observed for up to 2 hours before being discharged home [8].
  
  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

6.3 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 [8].

6.4 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 [7].

Back to top

7. INVESTIGATIONS

7.1 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 [1,9]. The best time to measure serum tryptase is between 1- 2 hours (but no longer than 4 hours) after symptoms begin [9].

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).

7.2 Tryptase measurement is not routinely recommended for food-related anaphylaxis IF the cause is known.

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

Back to top

8. DISCHARGE

8.1 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.

8.2 Children discharged from inpatient wards or the A&E department who require follow-up in allergy clinic include [8]:

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

8.3 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 the 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.

8.4 Children who have presented with anaphylaxis should be discharged with self-injectable adrenaline/epinephrine (i.e. ‘EpiPen’) for future first-aid management of anaphylaxis [8].

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.

8.5 Prior to discharge, family and child where appropriate, should be instructed on when and how to use self-injectable adrenaline in future.

If a child is to be prescribed an adrenaline/epinephrine auto injector, and the child is seen ‘out of hours’ or if the Children’s Allergy Nurse Specialists are unavailable to deliver the training - please direct the patient and their family to the following LTHT Training videos:

EpiPen Training Video - www.lchtv/allergy-epi-pen

Jext Training Video - www.lchtv.com/jext-adrenaline-auto-injector

Discharge Checklist

1. If a child presents with an allergic reaction during normal working hours or is admitted, consult with a member of the allergy team to discuss further management, evaluation on the ward & appropriate follow-up arrangements.
   • Dr Hodge, Paediatric Allergy Consultant (ph. 392 0670)
   • Dr Semic-Jusufagic, Paediatric Allergy Consultant (392 0670)
   • Children’s Allergy Nurse Specialists (ph. 392 0681)
     
     Allergy Nurses email - leedsth-tr.allergy@nhs.net
2. Arrange appropriate follow-up in the paediatric allergy clinic (see Allergy Clinic Referral Form).
   
   
3. Take blood (2 - 4ml clotted) serum tryptase for anaphylactic reactions, if indicated (see 7.1-7.3).
   
   
4. Prescribe and explain appropriate medications:
   • Antihistamine [10]
     • Under 2 years of age - Chlorphenamine 1 mg (2.5 mls)
     • 2-6 years of age - Cetirizine 5 mg (5 mls)
     • Over 6 years of age - Cetirizine 10 mg (10mls)
   • Bronchodilator (if indicated)
   • TWO self-injectable adrenaline auto-injectors (AAI’s) if indicated
     • 0.15mg (15-25kg)
     • 0.3mg (>25kg)
       
       If patient already has an AAI prescribed - ensure that existing AAI’s are still in date and are the correct dose for their weight
       
       
5. Anaphylaxis & adrenaline auto-injector (AAI) training may be facilitated during normal working hours (Monday to Friday 0900-1700).
   Contact Children’s Allergy Nurse Specialists on 20681 or email leedsth-tr.allergy@nhs.net.
   
   
6. If Children’s Allergy Nurses are not available, ensure child and family receive self-injectable adrenaline/epinephrine training
   • Refer to Training Videos - (see 8.5)
   • Allergy Management Plans - download from

https://www.bsaci.org/professional-resources/resources/paediatric-allergy-action-plans/