Anaphylaxis (Pediatric) Management

Pharmacological therapy

Immediate Management  

In anaphylaxis, Epinephrine is administered 1:1,000 dilution (0.01 mg/kg) at a dose of 0.01 mL/kg (max dose: 0.3 to 0.5 mL or 0.3 to 0.5 mg) every 5 to 15 minutes, until condition stabilizes. The dose is equivalent to 10 mcg/kg. IM injection into the lateral side of the mid thigh is the best route and site to give Epinephrine to treat an anaphylactic reaction. IM injections in the thigh produce more rapid absorption and higher plasma Epinephrine concentration than IM injection in the arm.  

The following doses per patient weight are recommended:

• Patients weighing 7.5 to 15 kg: 0.1 mg (may consider giving 0.15 mg in patients weighing 7.5 to 10 kg)
• Patients weighing 15 to 30 kg: 0.15 mg
• Patients weighing ≥30 kg: 0.3 mg

Inhaled Epinephrine via metered dose inhalers or nebulizers may be beneficial to treat laryngeal edema or persistent bronchospasm in cases where IV route cannot be obtained or despite a previous IM Epinephrine dose. Repeated doses of Epinephrine are administered until clinical improvement is achieved. If there is no improvement after 3 to 4 doses, the patient should be transported to an emergency medical facility.

Subsequent Management  

Epinephrine IV Infusion  

Epinephrine IV infusion is indicated during cardiac arrest or in profoundly hypotensive patients who have failed to respond to several injection doses of Epinephrine and IV fluid replacement. This may be prepared by adding 1 mg (1 mL) of 1:1,000 dilution of Epinephrine to 250 mL of D5W to yield 4 mcg/mL. It is infused at a rate of 1 to 4 mcg/min with a max of 10 mcg/min for adolescents. An alternative is the “rule of 6”, 0.6 times body weight (kg) = number of mg diluted in 100 mL of saline, then 1 mL/hour delivers 0.1 mcg/kg/min. Continuous cardiac monitoring is recommended due to potential for lethal arrhythmias and to minimize the risk of overtreatment and Epinephrine toxicity. Possible Epinephrine toxicity is considered instead of worsening anaphylaxis in patients with normal or elevated SBP who are nauseous, vomiting, shaky or tachycardic. 

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Nonpharmacological

Immediate Management  

Prompt assessment and treatment are critical as death can ensue rapidly. A rapid assessment of airway, breathing, circulation, and level of consciousness is done. Triggering allergens are removed if possible (induce vomiting if food-induced, stop drug intake or infusion, etc). The patient is placed in the supine position with the lower extremities elevated if tolerated (left lateral position for vomiting patients or in a comfortable position for patients with dsypnea). Infants and young children should be held flat or horizontally in the carer’s arm and not upright over the shoulder. Until fully stabilize, do not let the patient sit up suddenly once supine as doing so can cause hypotension and death.  

Subsequent Management  

It is important to establish and maintain the airway. Endotracheal tube, cricothyrotomy or needle cricothyrotomy may be performed if indicated.  

Oxygen (O₂)  

High flow O₂ (6 to 8 L/min) via non-rebreathing mask or endotracheal tube in patients experiencing respiratory symptoms, hypoxemia, or hypotension related to anaphylaxis should be provided. Continuous pulse oximetry and arterial blood gas determination should guide O₂ therapy.  

Fluid Support  

IV access is maintained using wide bore needles or cannulas (14 to 16 gauge). Rapid administration of 1 to 2 liters of isotonic (0.9%) saline solution may be indicated. In children, hydration is at 10 mL/kg for the first 5 to 10 minutes. For hypotensive patients or those with cardiovascular collapse, IV administration of normal saline at 20 mL/kg is recommended. If IV access is delayed or impossible, an introspective route can be used. Inotropic support with Dopamine or Epinephrine infusion should be started if >40 mL/kg is needed. Invasive BP monitoring may be required. It is important to monitor the patient for signs of overtreatment (eg hypertension or pulmonary edema). 

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• Cardiopulmonary resuscitation and advanced cardiac life support measures
• Prolonged resuscitation efforts are encouraged
• High-dose Epinephrine (IV)
• Rapid volume expansion
• Consider extracorporeal membrane oxygenation (ECMO) if available
• Transport to ICU, as setting dictates

Patient Observation  

Patient observation is considered in post-anaphylactic patients due to the risk of biphasic reaction or possible recurrence as the effect of Epinephrine wears off. Biphasic reaction is the recurrence of symptoms after the initial episode of anaphylaxis has resolved without any further exposure to the trigger. It is associated with a greater severity of an initial reaction and persistence of the reaction. It occurs in 1-23% of anaphylaxis cases. The onset of the second phase of the reaction ranges from 1 to 72 hours after the initial reaction. Risk factors for a biphasic reaction include more severe initial presentation of anaphylaxis, initial reaction requiring >1 dose of Epinephrine, and delay in Epinephrine administration. Children <16 years old should be admitted for observation. Young people ≥16 years old should be observed for 6 to 12 hours from onset of symptoms. The period of observation will vary from 4 to 24 hours depending on the clinical situation. Patients with respiratory symptoms would require 6 to 8 hours of observation. Patients with hypotension or shock will require 12 to 24 hours of observation in the ICU. Longer periods of observation may be provided to patients with risk factors for developing severe anaphylaxis, those who required >1 dose of Epinephrine, or protracted anaphylactic episode. Patients should be followed up for 7 days after the observational period for the occurrence of biphasic reactions. 

Patient, Guardian, and Caregiver Education  

Patient, parents, and caregivers should be able to apply the following objectives:

• Identify and avoid triggers and cofactors
• Recognize early warning signs and symptoms of anaphylaxis
• Risk of biphasic reaction
• What to do should an anaphylaxis episode occur again
• Medications prescribed and their indication
• Training on the correct use and timing of Epinephrine injector
• The need for referral to an allergy specialist (including the process of referral)
• Information about support groups

Education and management plans should be individualized. At-risk patients should be protected by wearing accurate and up-to-date medical identification listing their confirmed trigger factors, relevant comorbidities, concurrent medications, and emergency contact details. Individualized instruction and coaching may help to diminish the anxiety among caregivers.  

Indications for Prescribing Self-injectable Epinephrine

• History of cardiovascular or respiratory reaction to an allergen (eg food, latex, insect sting)
• History of Hymenoptera venom allergy in untreated patients with more than cutaneous or mucosal systemic reactions or high risk of re-exposure
• History of treatment with Hymenoptera venom immunotherapy in patients with more than cutaneous or mucosal systemic reactions at high risk of relapse
• Food-induced anaphylaxis associated with exercise
• At least 2 auto-injections should be prescribed and carried at all times by patients at risk for food-induced anaphylaxis
• Patients with food allergy and co-existent persistent asthma
• Idiopathic anaphylaxis
• Children with severe skin involvement (>50% body surface), increased basal serum tryptase levels and with blistering in the first 3 years of life
• Previous reaction to small amounts of food
• History of only a previous mild reaction to a tree nut or peanut
• Severe allergic reaction in an adolescent
• Remote location without rapid access to medical facility
• History of Hymenoptera venom or drug allergy in patients with more than cutaneous or mucosal systemic reactions and cardiovascular disease
• History of oral immunotherapy for food allergy

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• To take a full allergy-focused history
• To perform tests to determine the cause of anaphylaxis and confirm the diagnosis
• To develop an individualized management plan and be able to train the patient and caregivers to ensure implementation of the management plan
• To offer information on avoidance and control of confirmed trigger factors
• If symptoms are recurrent or difficult to control
• If the patient is a candidate for immunotherapy or desensitization
• If daily medications for prevention are required