Pediatric Anaphylaxis Management
Anaphylaxis is a clinical diagnosis requiring immediate intramuscular (IM) adrenaline — there is no absolute contraindication, and delay is the strongest predictor of fatality. Do not wait for hypotension; respiratory or circulatory compromise with a likely allergen exposure is enough.
Recognition (any one criterion)
| Criterion | Features |
|---|---|
| 1. Acute onset (skin/mucosa) + | Respiratory compromise (wheeze, stridor, hypoxia) or reduced BP/end-organ dysfunction |
| 2. ≥2 systems after likely allergen | Skin/mucosa, respiratory, cardiovascular (hypotension/collapse), persistent GI (cramping, vomiting) |
| 3. Hypotension after known allergen | Age-specific low systolic BP or >30% drop |
Age-specific hypotension: <70 mmHg (1–12 mo); <70 + (2 × age in yr) (1–10 y); <90 mmHg (>10 y).
First-line: IM adrenaline
Adrenaline 1:1000 (1 mg/mL), IM into the anterolateral thigh (vastus lateralis). Dose 0.01 mg/kg, max 0.3 mg in children (0.5 mg in adolescents/adults). Repeat every 5 minutes if no improvement.
| Weight | Approx. age | Adrenaline 1:1000 dose | Volume (1 mg/mL) | Auto-injector |
|---|---|---|---|---|
| <7.5 kg | <6 mo | 0.01 mg/kg | 0.01 mL/kg | Use ampoule + syringe |
| 7.5–15 kg | ~6 mo–3 y | ~0.10–0.15 mg | 0.10–0.15 mL | 0.15 mg (Jr) |
| 15–25 kg | ~3–7 y | 0.15–0.25 mg | 0.15–0.25 mL | 0.15 mg (Jr) |
| 25–30 kg | ~7–10 y | 0.25–0.30 mg | 0.25–0.30 mL | 0.30 mg |
| ≥30 kg | >~10 y | 0.30 mg | 0.30 mL | 0.30 mg |
| Adult-sized | adolescent | 0.30–0.50 mg | 0.30–0.50 mL | 0.30 mg |
Auto-injectors come in fixed 0.15 mg and 0.30 mg strengths. In a weighed inpatient, an ampoule-drawn weight-based dose is more precise; in the community, give the nearest auto-injector strength without delay.
Positioning
| State | Position |
|---|---|
| Hypotension / faint | Supine, legs elevated |
| Breathing difficulty | Sitting up |
| Vomiting | Recovery position |
| Pregnant | Left lateral |
Do not stand or sit the patient up suddenly — fatal “empty ventricle” cardiac arrest is reported on sudden uprighting.
Adjuncts (after adrenaline — never instead of it)
| Therapy | Detail |
|---|---|
| High-flow oxygen | Titrate to SpO₂ ≥94% |
| IV fluid bolus | Crystalloid 10–20 mL/kg, repeat as needed for shock |
| Inhaled salbutamol | For bronchospasm not relieved by adrenaline |
| Inhaled/nebulised adrenaline | Adjunct for upper-airway oedema/stridor |
| H1 antihistamine | Symptomatic urticaria/itch only — does not treat anaphylaxis |
| Corticosteroid | No longer routinely recommended; does not relieve acute obstruction |
Reminders
- IM adrenaline is first-line and life-saving; antihistamines and steroids are not.
- Observe for biphasic reactions — typically 4–12 h; longer observation if severe or repeat dosing was needed.
- Two doses without improvement → escalate to IV adrenaline infusion by an experienced clinician.
- Prescribe an auto-injector and an allergy-action plan at discharge.
Calculate the exact weight-based dose with the weight-based dose calculator.
Decision support for qualified clinicians only — verify against current primary guidelines and your clinical judgement.