Peanut Allergy Reaction: Signs, Risks & What to Do

Key Points

• Peanut allergies can trigger severe, life-threatening reactions.
  
• Symptoms range from mild itchiness to anaphylaxis.
  
• Fast EpiPen use and calling 000 saves lives.
  
• Long-term safety relies on avoidance, ASCIA action plans, and medical follow-up.
  
• Research in Australia is exploring new therapies.
  

What Is a Peanut Allergy Reaction?

A peanut allergy reaction occurs when the immune system mistakenly identifies peanut proteins as harmful. This triggers chemicals like histamine, leading to allergy symptoms.

Unlike food intolerances (which don’t involve the immune system), peanut allergies can cause severe, even life-threatening responses.

How Peanut Allergies Work

Even a trace of peanut can cause a reaction. The immune system produces IgE antibodies, which bind to mast cells. These release histamine, leading to swelling, itching, or difficulty breathing.

Prevalence in Australia

Peanut allergy affects about 3% of Australian children and is also seen in adults.
According to ASCIA, cases have increased in recent decades, matching global trends.

Common Triggers and Hidden Sources

Peanut allergy triggers include:

• Peanut butter
  
• Peanut oil (especially unrefined)
  
• Baked goods (cakes, biscuits)
  
• Asian sauces (satay, hoisin)
  
• Confectionery and desserts
  

Hidden sources of peanuts include cross-contaminated foods, catered meals, or workplace snacks. Even small amounts can cause reactions.

Symptoms of a Peanut Allergy Reaction

Mild to Moderate Symptoms

• Itchy mouth, tongue, or throat
  
• Hives or redness
  
• Runny nose or sneezing
  
• Nausea or mild stomach pain
  

Severe Symptoms (Anaphylaxis)

• Difficulty breathing or wheezing
  
• Swelling of the tongue or throat
  
• Dizziness or fainting
  
• Rapid drop in blood pressure
  
• Loss of consciousness
  

Delayed Reactions

Rarely, symptoms may appear hours later. These require medical attention as well.

How Fast Do Reactions Occur?

Most reactions occur within 5–30 minutes. Some happen faster, so immediate action is essential.

Immediate Actions During a Reaction

Using an EpiPen (Emergency Adrenaline)

1. Remove the EpiPen from its case.
   
2. Hold firmly – blue to the sky, orange to the thigh.
   
3. Remove the blue safety cap.
   
4. Push the orange tip into the outer mid-thigh (through clothing if needed).
   
5. Hold for 3 seconds.
   
6. Call 000 immediately.

When to Call Emergency Services

Call 000 if:

• The person has breathing difficulty.
  
• Anaphylaxis symptoms are present.
  
• You’re unsure about the severity.
  

Monitoring After an Episode

Hospital observation is required for at least 4 hours after adrenaline use. This ensures safety in case of a biphasic (second wave) reaction.

Diagnosis and Medical Evaluation

Testing methods:

• Skin prick test
  
• Blood test (RAST/ImmunoCAP)
  
• Oral food challenge (under supervision)
  

ASCIA recommends testing only in controlled medical settings.

What to Do After a First Reaction

• Book a GP appointment.
  
• Request a referral to an allergist.
  
• Keep a food and symptom diary.
  
• Avoid peanuts until fully assessed.
  

Long-Term Management of Peanut Allergies

Avoidance Strategies

• Always check food labels. FSANZ requires allergen labelling.
  
• Ask about ingredients when eating out.
  
• Be cautious of cross-contamination in shared environments, including food handling.
  

Emergency Action Plans

Use an ASCIA Action Plan for Anaphylaxis and ensure it’s available at home, work, and school.

Workplace Considerations

• Inform your employer of your allergy.
  
• Request peanut-free zones if possible.
  
• Train colleagues in emergency response.
  

Treatment Options and Emerging Therapies

• Antihistamines – relieve mild symptoms like hives.
  
• Adrenaline (EpiPen) – first-line, life-saving treatment.
  
• Oral Immunotherapy (OIT) – being studied in Australia but not yet standard care.
  
• Clinical trials at institutions like Murdoch Children’s Research Institute explore OIT and vaccine options.
  

Preventing Reactions and Raising Awareness

• Food standards: FSANZ requires allergen declarations; precautionary labels remain voluntary.
  
• Policies: Schools and workplaces often use nut-free zones and staff training.
  
• Awareness: ASCIA leads public campaigns to reduce risks.
  

FAQ 

What are the first signs of a peanut allergy?

Itchy mouth, hives, and nausea are common.

How soon do symptoms appear?

Usually within 5–30 minutes.

What should I do in a severe reaction?

Use an EpiPen immediately and call 000.

Can adults develop peanut allergies?

Yes, though more common in children, adult-onset cases occur.

What foods should be avoided?

Any containing peanuts or made in facilities with peanut cross-contact.

Is there a cure?

No cure yet, but OIT and other therapies are being tested.