Synopsis
Recognise anaphylaxis without waiting for skin signs, give correctly concentrated intramuscular adrenaline promptly, manage refractory physiology and discharge children with specialist referral and a rehearsed auto-injector plan.
- Diagnose anaphylaxis clinically from sudden airway, breathing or circulation compromise, usually with skin or mucosal change; never wait for rash before treating dangerous physiology.
- Intramuscular adrenaline is first-line: use 1 mg/mL solution, give 10 micrograms/kg into the anterolateral thigh, maximum 500 micrograms, and repeat after five minutes if needed.
- When an exact weight is unavailable, RCUK age doses are 100–150 micrograms below six months, 150 micrograms from six months to six years, 300 micrograms from six to 12 years and 500 micrograms over 12 years.
- Lay the child flat with legs raised; allow supported sitting for severe breathing difficulty, recovery position if unconscious and pregnant patients on the left side, but do not allow standing or walking.
- Give high-concentration oxygen for critical illness, obtain monitoring and intravenous or intraosseous access and use a rapid 10 mL/kg crystalloid bolus for shock, reassessing for repeat fluid.
- Antihistamines treat persistent skin symptoms only after airway, breathing and circulation recovery; corticosteroids are not routine emergency treatment and do not replace adrenaline.
- After two appropriate intramuscular doses with persistent dangerous features, start an intravenous adrenaline infusion only through an expert monitored refractory-anaphylaxis protocol.
- Serum tryptase can support later investigation in selected severe, venom, medicine or idiopathic reactions, but sampling never delays treatment and a normal result does not exclude food anaphylaxis.
- Before discharge, refer to specialist allergy, prescribe the correct auto-injector devices, train with the actual brand, provide a written plan and ensure the child has access to two devices.
- Observation is individualised by severity, treatment response, comorbidity, biphasic risk, supervision and access to emergency care; children should be managed in an appropriate paediatric setting.
Key red flags
Hoarse voice, stridor, tongue swelling, persistent cough, wheeze, hypoxia, hypotension, collapse or altered consciousness requires adrenaline immediately.
Do not allow a child with anaphylaxis to stand or walk because abrupt venous return loss can precipitate cardiovascular collapse.
Persistent airway, breathing or circulation problems after two intramuscular adrenaline doses defines refractory anaphylaxis and needs expert intravenous adrenaline infusion and critical care.
Beta-blocker exposure, mast-cell disease, severe asthma, delayed adrenaline or a continuing absorbed allergen increases severity and biphasic risk.
Skin signs are absent in some anaphylaxis episodes, while skin signs alone without airway, breathing or circulation compromise do not automatically define anaphylaxis.
A child treated for anaphylaxis needs paediatric observation, specialist allergy referral, injector provision and training before discharge, not simple antihistamine advice.
Investigation priorities
Identify life-threatening airway, breathing and circulation involvement without delaying treatment for tests.
Management branches
Sudden airway, breathing or circulation compromise suggests anaphylaxis.
- Call for help, stop the trigger if feasible and position the child safely without standing.
- Give 1 mg/mL adrenaline intramuscularly into the anterolateral thigh and start monitoring.
- Repeat after five minutes if dangerous features persist while supporting oxygenation and circulation.
Hypoxia, bronchospasm or shock continues during first-line treatment.
- Give high-concentration oxygen and obtain intravenous or intraosseous access without delaying adrenaline.
- Administer 10 mL/kg isotonic crystalloid rapidly for shock and reassess for further fluid.
- Use inhaled bronchodilator as an adjunct for wheeze and prepare early airway expertise.