Emergencies

Anaphylaxis — Severe Allergic Reaction

2025-08-14 • Updated 2025-09-13

Intro

Food and environmental allergies are common, but anaphylaxis is a severe, life-threatening allergic reaction. It can happen within minutes of exposure to an allergen, and requires immediate emergency action. Even a tiny exposure can trigger a reaction in sensitive individuals.

Key Points

• Anaphylaxis is a medical emergency — use epinephrine (adrenaline) immediately.
• Common triggers: peanuts, tree nuts, shellfish, milk, eggs, insect stings, certain medicines.
• Symptoms can progress quickly — from hives and swelling to breathing difficulty and collapse.
• Always call emergency services, even after epinephrine use.
• People at risk should carry an auto-injector and action plan at all times.

Common Allergens

• Peanuts and tree nuts
• Shellfish and fish
• Milk and eggs
• Wheat and soy
• Sesame
• Insect stings and some medicines (e.g., antibiotics, NSAIDs)

Symptoms

• Mild/moderate: itching, hives, swelling of lips/face, abdominal pain, vomiting
• Severe (anaphylaxis): difficulty breathing, wheezing, swelling of tongue/throat, dizziness, fainting, collapse

First Aid for Anaphylaxis ⚠️

1. Use epinephrine auto-injector immediately (e.g., EpiPen).
2. Call emergency services.
3. Lay the person flat with legs elevated — unless breathing is very difficult (then allow sitting up).
4. If no improvement after 5–10 minutes, give a second dose if available.
5. Monitor breathing and circulation — be prepared to start CPR if necessary.

Prevention

• Read food and medicine labels carefully.
• Avoid cross-contamination when preparing food.
• Inform restaurants, schools, and workplaces about allergies.
• Carry an action plan and wear medical alert jewellery.

FAQ

Q: Why use epinephrine first and not antihistamines?
A: Epinephrine is the only life-saving treatment for anaphylaxis. Antihistamines may help mild symptoms (like hives) but do not stop airway or circulation collapse.

Q: Do I still need to go to the hospital if symptoms improve?
A: Yes. A reaction can return (biphasic reaction), so medical monitoring is essential.

Q: Can children outgrow food allergies?
A: Some do (e.g., milk or egg), but others (like peanut and tree nut) often persist. Always follow up with an allergy specialist.

Further Reading

• American College of Allergy, Asthma & Immunology — Food Allergy
• Australasian Society of Clinical Immunology and Allergy — Anaphylaxis Resources
• World Allergy Organization

Related Guides

• Emergencies — Guide Hub
• Chest Pain: When to Call 911 vs Wait for a Doctor
• Severe Bleeding — First Aid
• CPR — First Aid Guide
• Stroke — Act FAST

References

Simons, F.E.R., et al. (2020). World Allergy Organization anaphylaxis guidance 2020. World Allergy Organization Journal, 13(10), 100472.

⚠️ Educational only; not a substitute for professional medical advice. Always call emergency services immediately if anaphylaxis is suspected.

• #allergies
• #anaphylaxis
• #emergency
• #first aid
• #immune system