Tree Nut Allergy

Tree Nut Allergy Guide: Symptoms, Causes, Diagnosis and Treatment

Overview

Tree nut allergy is an allergic reaction to proteins found in nuts that grow on trees, such as almonds, walnuts, hazelnuts, cashews, pistachios, Brazil nuts and macadamia nuts. It is one of the most common food allergies and can cause reactions ranging from mild symptoms to severe anaphylaxis.

Tree nut allergies often begin in childhood and may last throughout life. While some people are allergic to several types of tree nuts, others may only react to specific nuts. Testing with an allergy specialist can help determine which nuts must be avoided.

Tree nuts are different from peanuts, which are legumes rather than true nuts. However, some people with peanut allergy may also be allergic to tree nuts.

Symptoms

Diagnosis

If a tree nut allergy is suspected, a doctor may refer you to an allergy specialist for further assessment. Diagnosis usually begins with a detailed medical history, including the symptoms experienced and the foods eaten before the reaction.

Testing may include:

• Skin prick tests or blood tests to look for allergic antibodies
• Oral food challenge tests (carried out under medical supervision)
• Testing across multiple tree nuts to determine which nuts must be avoided and which may still be safe to eat

An allergy specialist will interpret test results alongside medical history, as tests alone do not always confirm a true food allergy.

Living with Tree Nut Allergy

• Shopping: In many countries, peanuts and tree nuts must be clearly identified on food packaging. Always read ingredient labels carefully, even on products you buy regularly, as recipes and manufacturing processes can change.
• Eating out: Tell restaurant staff about your nut allergy and ask how dishes are prepared. It’s important to check for both nut ingredients and the risk of cross-contamination.
• Cross-contact: Tree nuts can appear in foods such as mixed nuts, nut butters, nut oils, desserts, pesto, praline, marzipan and some sauces. Cross-contact can occur if foods are prepared using the same equipment or surfaces. It can also happen during manufacturing, which is why precautionary labels such as “may contain nuts” should be taken seriously.
• Air travel: Most airlines cannot guarantee a nut-free environment. Consider wiping down tray tables and armrests and bring safe snacks with you.

Emergency Action

Mild allergic symptoms can often be treated with an antihistamine.

However, if there are signs of a severe allergic reaction — such as difficulty breathing, swelling of the throat or tongue, wheezing, sudden dizziness, or collapse — this is a medical emergency. Call your local emergency number immediately and use an adrenaline auto-injector if one has been prescribed.

Adrenaline auto-injectors commonly prescribed include:

• EpiPen® (adult and junior doses)
• Jext® (adult and junior doses)
• Auvi-Q® (available in some countries)

People at risk of severe allergic reactions are usually advised to carry two auto-injectors at all times, in case a second dose is needed.

After using an adrenaline auto-injector, medical attention is still required, as symptoms can return.

Friends, family members, teachers, and carers should know where the devices are kept and how to use them. Training devices and demonstration videos are available from the manufacturers’ websites.

Outgrowing Tree Nut Allergy

Tree nut allergies are less commonly outgrown than some other food allergies. While a small number of children may eventually tolerate certain tree nuts, many people continue to have the allergy into adulthood.

In some cases, people may be allergic to only one or two types of tree nuts while being able to safely eat others. Regular reviews with an allergy specialist can help determine whether the allergy is still present and whether supervised food challenges or reintroduction may be appropriate.

Future Treatments

Research into new treatments for food allergies is ongoing. Some emerging approaches include:

Oral immunotherapy (OIT) – gradually introducing very small amounts of the allergen under medical supervision to help build tolerance.

Epicutaneous immunotherapy – skin patch treatments designed to slowly desensitise the immune system.

New medicines and biological therapies – researchers are studying treatments that may help reduce the severity of allergic reactions.

Many of these treatments are still being studied and may not be suitable for everyone.

For now, the safest approach remains avoiding trigger foods, checking ingredient labels carefully, and carrying emergency medication if prescribed.

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When to Seek Medical Advice

Speak to a doctor or healthcare professional if you think you or your child may have a food allergy. Symptoms such as hives, swelling, stomach pain, vomiting, or breathing problems after eating certain foods should always be assessed by a medical professional.

Urgent medical attention is needed if symptoms of a severe allergic reaction (anaphylaxis) occur, including difficulty breathing, swelling of the throat or tongue, wheezing, dizziness, or collapse.

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Resources

• NHS – Food Allergy Guidance
• Allergy UK
• British Society for Allergy & Clinical Immunology (BSACI)

These organisations provide trusted information, advice, and support for people living with allergies.

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Medical Disclaimer

This guide is provided for general information only and is not a substitute for professional medical advice, diagnosis, or treatment.

Always seek advice from your doctor, allergy specialist, or another qualified healthcare professional if you have concerns about allergies, symptoms, or treatment.

If you believe you or someone else may be experiencing a severe allergic reaction (anaphylaxis), seek emergency medical assistance immediately.

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