Pediatric Anaphylaxis

Key considerations: Biphasic anaphylaxis (recurrence 1-72 hours later), Refractory anaphylaxis, Anaphylaxis masquerading as asthma or urticaria

Cannot miss

history: Exact exposure and timing of symptom onset; Previous allergic reactions — severity; Asthma history (increases mortality risk); Prior epinephrine use; All medications taken; Exercise-dependent food allergy (exercise within 4h of food); exam: Airway: stridor, voice changes, lip/tongue swelling; Breathing: wheeze, respiratory rate, SpO2; Circulation: BP, HR, perfusion, capillary refill; Skin: urticaria (hives), angioedema, flushing; GI: vomiting, abdominal pain, diarrhea; Mental status; labs: Serum tryptase: draw within 1-2 hours of symptom onset (elevated = mast cell degranulation — confirms anaphylaxis); Not needed for acute management; imaging: CXR only if concern for alternative diagnosis; bedside: Continuous monitoring: SpO2, BP, HR; IV access — preferably 2 large bore

immediate: EPINEPHRINE IM 0.01mg/kg (1:1000) — max 0.3mg in child, 0.5mg in adolescent; Give in lateral thigh — do NOT delay for anything else; Repeat q5-15min if no improvement (up to 3 doses); Position supine with legs elevated (unless vomiting or airway swelling); general: Remove trigger if possible (stop IV drug infusion, remove stinger); Supplemental O2; IV fluid bolus 20mL/kg NS if hypotensive; specific: diagnosis: Mild-moderate anaphylaxis; steps: IM epinephrine immediately; Diphenhydramine 1mg/kg IV/IM (max 50mg); Famotidine 0.25mg/kg IV (max 20mg); Dexamethasone 0.6mg/kg IV/PO (max 16mg) — prevents biphasic reaction; Albuterol nebulization if wheezing; diagnosis: Severe/refractory anaphylaxis; steps: Repeat IM epinephrine q5min x3; If not responding: epinephrine drip 0.1-1 mcg/kg/min; Aggressive IV fluid resuscitation: 20mL/kg boluses, repeat; Glucagon 20-30mcg/kg IV if on beta-blockers; Prepare for intubation if airway edema progressing

admit: Any anaphylaxis requiring >1 dose of epinephrine; Persistent symptoms after initial treatment; History of biphasic reactions; Severe reaction or refractory anaphylaxis; Poor social situation or distance from medical care; discharge: Complete resolution of symptoms after single epinephrine dose; Observe minimum 4-6 hours (some guidelines recommend 6-8 hours for high risk); Prescribe epinephrine auto-injector (EpiPen Jr or regular based on weight); Allergy referral within 2 weeks; Written anaphylaxis action plan; consults: Allergy/immunology for follow-up (outpatient); PICU if refractory anaphylaxis

EPINEPHRINE is the ONLY first-line treatment for anaphylaxis — antihistamines and steroids are ADJUNCTS, not replacements
Never delay epinephrine — delayed administration is the #1 risk factor for fatal anaphylaxis
Biphasic reactions occur in up to 20% of children — steroids may reduce risk. Observe 4-6 hours minimum
Fatal food anaphylaxis risk factors: adolescent age, known asthma (especially poorly controlled), peanut/tree nut allergy, delayed epinephrine

WAO/EAACI Anaphylaxis Guidelines 2021, AAP Anaphylaxis Management in the ED. Last reviewed: 2024-11-01