A severe, life-threatening systemic hypersensitivity reaction characterised by rapid onset and involvement of multiple organ systems, most often mediated by IgE in response to allergens.
Previous anaphylaxis
Atopy (asthma, eczema, allergic rhinitis)
Mast cell disorders
Family history of severe allergy
Foods: peanuts, tree nuts, shellfish, eggs, milk
Drugs: penicillin, NSAIDs, anaesthetic agents
Insect stings (bees, wasps)
Latex, exercise, idiopathic causes
Skin: urticaria, angioedema
Respiratory: wheeze, stridor, dyspnoea
Cardiovascular: hypotension, tachycardia, syncope
GI: abdominal pain, vomiting, diarrhoea
Neurological: dizziness, confusion
🚨 Airway involvement or circulatory collapse requires immediate intervention.
IM adrenaline (epinephrine) into anterolateral thigh (age-appropriate dose)
Position supine with legs elevated
High-flow oxygen, IV access, fluids if hypotensive
Repeat adrenaline every 5 minutes if no response
Adjuncts: antihistamines, corticosteroids, bronchodilators
Post-event: prescribe 2 adrenaline auto-injectors, arrange allergy referral, provide written action plan
