Table of Contents

Tree Nut Allergies in Australia: Symptoms, Diagnosis & Management

Key Takeaways on Tree Nut Allergies

Tree nut allergies are one of the most common and serious food allergies in Australia.
Symptoms range from mild hives or nausea to life-threatening anaphylaxis.
Common allergenic nuts: almonds, cashews, walnuts, pistachios, hazelnuts, pecans, Brazil nuts, and macadamias.
Peanuts are legumes, not tree nuts, but reactions may overlap.
Diagnosis uses skin prick, blood IgE tests, or supervised food challenges.
Cross-reactivity is common: e.g., cashew ↔ pistachio, walnut ↔ pecan.
Management: strict avoidance, allergen label checks, and always carrying an EpiPen.
FSANZ laws in Australia require clear allergen labelling.
Adults can develop nut allergies later in life (adult-onset).
Research into oral immunotherapy is underway but not yet standard treatment.

What Are Tree Nut Allergies?

Definition and Overview

Tree nut allergies occur when the immune system mistakenly reacts to proteins in nuts such as almonds, cashews, or walnuts. Unlike peanut allergies, which involve legumes, tree nut allergies involve nuts that grow on trees.

Important: Foods like coconut, nutmeg, and shea nuts are not true tree nuts and rarely cause reactions in people with nut allergies.

Tree Nuts vs Peanuts

Tree nuts: almonds, cashews, walnuts, pistachios, hazelnuts, pecans, macadamias, Brazil nuts.
Peanuts: legumes (related to beans and lentils).
Cross-allergy is possible but not guaranteed.

Prevalence in Australia

Around 2–3% of Australian children and ~1% of adults live with a tree nut allergy.
Tree nuts are a leading cause of food-induced anaphylaxis in Australia.

Common Tree Nuts That Cause Allergies

Tree Nut	Common Uses	Allergy Notes
Almonds	Flour, almond milk, pastries, snack bars	Common in processed foods
Cashews	Vegan cheese, sauces, curries	Cross-reacts with pistachios
Walnuts	Baked goods, salads, granola	Linked with pecan allergy
Pistachios	Ice cream, snacks, desserts	Strongly related to cashews
Hazelnuts	Nutella, spreads, confectionery	Widely allergenic
Pecans	Pecan pie, baked goods	Cross-reactive with walnuts
Brazil Nuts	Trail mixes, oils	Less common but severe reactions possible
Macadamias	Biscuits, chocolates (esp. in Australia)	Important in AU context

Symptoms of a Tree Nut Allergy Reaction

Mild to Moderate Symptoms

Itchy mouth, throat, or lips
Hives or skin rash
Sneezing, runny nose
Nausea, stomach pain, or diarrhoea

Severe Reaction (Anaphylaxis)

Difficulty breathing, wheezing
Swelling of lips, tongue, or throat
Rapid heartbeat, low blood pressure
Dizziness, fainting, unconsciousness

Anaphylaxis is a medical emergency. Use an EpiPen immediately and call 000.

How Tree Nut Allergies Are Diagnosed

Skin prick test – measures skin reaction to nut protein.
IgE blood test – measures immune response.
Food challenge – supervised by an allergist.

Cross-Reactivity Between Nuts and Other Foods

Nut-to-Nut: Cashew ↔ Pistachio; Walnut ↔ Pecan.
Tree nuts & Peanuts: Different families, but many have both.
Misunderstood “Nuts”:
- Coconut = fruit, usually safe.
- Nutmeg = seed, not a nut.
- Shea nut = skincare, rarely allergenic.

Living With a Tree Nut Allergy: Practical Tips

Read labels carefully (FSANZ laws require allergens to be listed).
Ask about cross-contamination when eating out.
Use separate utensils and storage in shared kitchens.
Consider carrying a medical alert bracelet.

Tree Nut Allergies in the Workplace

Inform HR and colleagues.
Store food separately.
Employers must make reasonable adjustments under Australian law.
Food handling training helps reduce risks.

Emergency Preparedness & Treatment

Use an EpiPen in the outer thigh at the first sign of anaphylaxis.
Always carry two devices.
Call 000 immediately, even after using an EpiPen.
Keep an emergency action plan at school, work, and home.

Tree Nut Allergy in Children vs Adults

Children: Some may outgrow nut allergies (retesting advised).
Adults: Can develop nut allergies later in life (adult-onset).

Future of Tree Nut Allergy Management

Oral immunotherapy (OIT) is under clinical trials in Australia.
Support groups and advocacy organisations (e.g., Allergy & Anaphylaxis Australia) provide education and community support.