Anaphylaxis - Paediatric



Key Points:

Anaphylaxis is a severe allergic response manifest by typical skin features and involvement of one or more of the:

  • Respiratory system.
  • Cardiovascular system.
  • Gastrointestinal system.
OR
  • Any acute onset episode of bronchospasm or hypotension or upper airway obstruction where anaphylaxis is considered a possibility. Serum tryptase levels in consultation with a paediatric allergy specialist can be helpful when the diagnosis of anaphylaxis is uncertain.

Clinical

Signs and symptoms of anaphylaxis for each system includes:

  • Skin features (absent in approximately 20%): Urticaria, erythema, flushing or angioedema.
  • Respiratory (More common than cardiovascular symptoms in children): Itchy mouth or throat, tongue or throat swelling, rhinitis,cough, wheeze.
  • Cardiovascular: Tachycardia, pallor, light-headedness, lethargy, pallor, hypotension (late sign).
  • Gastrointestinal (Severe and persistent symptoms): Vomiting, abdominal pain, diarrhoea.

It is important to identify the risk factors for fatal anaphylaxis from a thorough history and plan to reduce these risks in consultation with the family:

  • Not lying child supine.
  • Delay to administration of adrenaline.
  • Poorly controlled asthma.
  • Adolescence.
  • Allergy to nut or shellfish.

Treatment

  • Assess ABC
  • High flow oxygen
  • IM Adrenaline (flow diagram for dose)
  • REPEAT IM Adrenaline @ 3-5 mins if required
  • Nebulised Adrenaline if airway obstruction
  • Treat ↓ BP with 20ml/kg fluid bolus
  • Consider Salbutamol nebs if wheeze
  • Antihistamines given for itch (not "collapse")
  • Early anaesthetic involvement if airway obstruction
  • Early ENT involvement if possibility surgical airway required

Management approach

Adrenaline dosing
Age (yrs) Wt Vol. Adrenaline
1 : 1000
Adrenaline
autoinjectors
<1 5-10 0.05 - 0.1 mL
1-2 10 0.1 mL 10-20 kg (1-5yrs) = 0.15 mg (green label) device
2-3 15 0.15 mL
4-6 20 0.2 mL
7-10 30 0.3 mL >20kg (>5y) = 0.3mg (yellow label) device
10-12 40 0.4 mL
>12 & adult >50 0.5 mL

Discharge criteria:

  • Patients should be observed for 6 hours following administration of adrenaline. The child must be symptom free at the time of discharge.
  • Fill in the allergy clinic referral form.
  • Prescribe 2 epipens (junior <30kg, or epipen >30kg).
  • Contact allergy CNS during working hours for education. Afterhours – educate using epipen trainer found in CNF office.
  • Give anaphylaxis action plan.

The child should be admitted overnight if:

  • Two or more adrenaline injections were required.
  • Lives a significant distance from medical services.
  • Poorly controlled asthma.
  • Ongoing symptoms.


Content by Dr Íomhar O' Sullivan 16/08/2014. Reviewed 01/08/2007. Last review Dr IOS/Dr Rory O'Brien 31/05/21