Peanut, Tree Nut and Seed Allergy

Frequently Asked Questions

This document has been developed by ASCIA, the peak professional body of clinical immunology/allergy specialists in Australia and New Zealand. ASCIA information is based on published literature and expert review, is not influenced by commercial organisations and is not intended to replace medical advice.

For patient or carer support contact Allergy & Anaphylaxis Australia or Allergy New Zealand.

ASCIA PC Peanut Treenut Seed Allergy FAQ 2024179.36 KB

Q 1: How common is peanut and tree nut allergy?

Peanut and tree nut allergy is most common in infants and young children, with 3% of infants having a peanut allergy, but may appear for the first time in adults.

Peanuts and tree nuts are one of the most common foods causing life threatening severe allergic reactions (anaphylaxis). Deaths from food allergy are rare in Australia but mild, moderate and severe allergic reactions are common.

Q 2: Is peanut a nut or legume?

Peanuts are legumes, like peas, lentils, chickpeas, and beans. The proteins in peanut are very different to those in tree nuts, which include almonds, Brazil nuts, cashews, hazelnut, macadamia nuts, pecans, pistachios, and walnuts. People with peanut allergy are not always going to be allergic to tree nuts.

Q 3: What does allergy to nuts or seeds mean?

The meaning of the terms ‘nuts, seeds and legumes’ can be confusing for people with allergies to these foods and their carers when trying to decide what foods to avoid.

Legume is often used to describe peanut as well as other plants like peas, lentils, and beans.
Tree nuts come from a range of different plant groups such as Rosaceae (almonds), Anacardiaceae (cashews), Proteaceae (macadamias), or Lecythidaceae (Brazil nuts).
Small seeds include sesame, sunflower, poppy, and pumpkin seeds. Many foods considered to be nuts are part of a seed, often with the outer fruit or coating removed, such as coconut.

Q 4: What are the signs and symptoms of an allergic reactions to peanuts, tree nuts or seeds?

Signs and symptoms of mild to moderate allergic reactions to foods include:

Swelling of the lips, face, eyes
Hives or welts on the skin
Abdominal pain, vomiting

Signs of anaphylaxis to foods include any one of the following:

Difficult or noisy breathing
Swelling of the tongue
Swelling or tightness in the throat
Wheeze or persistent cough
Difficulty talking or hoarse voice
Persistent dizziness or collapse
Pale and floppy (in young children)

Anaphylaxis is the most severe type of allergic reaction and should always be treated as a medical emergency. Anaphylaxis requires immediate treatment with adrenaline (epinephrine), which is injected into the outer mid-thigh muscle. Delayed treatment can result in fatal anaphylaxis.

Q 5: How is food allergy diagnosed?

Reliable diagnosis of food allergy is important. A doctor will ask a series of questions that may help to narrow down the list of likely causes of allergy, such as foods or medicines consumed that day, or exposure to stinging insects. This approach will help to exclude conditions that can sometimes be confused with food allergy.

Skin tests or blood tests for allergen specific IgE help confirm or exclude potential triggers. While the results of allergy tests are a useful guide in determining whether a person is allergic, they are not a reliable guide to how severe a reaction will be.

Q 6: Are there ‘allergy testing’ methods which are unproven and not recommended?

Some unorthodox/alternative practitioners offer unproven, non-evidence-based allergy ‘tests’ and ‘treatments’ that are not recommended by ASCIA.

These include cytotoxic food testing, kinesiology, hair analysis, vega testing, electrodermal testing, pulse testing, reflexology, bioresonance, Bryan’s or Alcat tests, VoiceBio, allergy elimination techniques and immunoglobulin G (IgG) to foods. These tests can result in misdiagnosis, ineffective treatments, costly and often dangerous dietary restrictions.

Q 7: What is the treatment for peanut, tree nut or seed allergy?

Avoidance of the allergen is the only proven treatment for peanut, tree nut or seed allergy. Removing these foods from the diet for most people usually does not affect their nutrition or growth. Children with food allergy should take their own food to school and be taught not to swap, share, or accept food from other people. In common eating and food preparation areas, where there are young children with severe peanut or tree nut allergy, nut-containing foods are best avoided.

In early childhood education/care centres with very young children, the risk of food contamination of common eating areas or toys is higher. All parents may be asked not to send nut containing foods in lunch boxes to reduce the risk of a reaction in one allergic child. This is not a policy that is considered necessary when caring for older children, although the use of nut or seed containing foods in cooking classes and science experiments is discouraged if there are students with peanut or tree of nut allergy in that class.

Q 8: How is peanut, tree nut or seed allergy managed?

People can learn to manage their peanut, tree nut or seed allergy with the guidance of their clinical immunology/allergy specialist. This knowledge and support can reduce anxiety around eating.

It is important for people with confirmed food allergy to:

Avoid confirmed food allergens.
Know the signs and symptoms of allergic reactions and know what to do when a reaction occurs.
Carry their adrenaline injector (if prescribed) and ASCIA Action Plan at all times.

ASCIA Action Plans for anaphylaxis are emergency response plans for anaphylaxis and are provided to people who are prescribed adrenaline injector devices. People with peanut, tree nut or seed allergy may have an accidental exposure because these foods can be hard to avoid.

Q 9: How can peanuts, tree nuts and seeds be avoided?

Peanuts, tree nuts and seeds are widely used in Western and Asian foods. This is a problem for people with severe peanut, tree nut or seed allergy. Laws require that any product containing peanut, tree nuts or sesame must be clearly labelled on the package.

It is important to check the labels of all foods before purchase and eating. Further information about reading food labels, food selection and allergen avoidance is available in the ASCIA dietary avoidance information sheets.

The risk of accidental exposure to food allergic trigger/s can never totally be removed.
Taking precautions when eating away from home will reduce or minimise your risk:

Contact the restaurant, café, or other food service that you plan to visit in advance and let them know about your food allergy.
Tell staff about your food allergy on arrival at a food service and ask them to let the chef know about your food allergy. Don't rely on the menu descriptions of what is in the food. Many salads have nuts or seeds added for texture. Nuts can be added to gravies and sauces too.
Teenagers or adults who are eating out may cautiously ‘touch test’ a small amount of the food on their outer lip before putting it in their mouth. Warnings such as a burning, chilli-like reaction, and tingling or swelling can be an alert that the food allergen is present.
Carry your adrenaline injector (if prescribed) and ASCIA Action Plan at all times.

Q 10: Is peanut oil safe for people with a peanut allergy?

Highly purified peanut oil contains little allergen. Refined peanut oils (not cold-pressed) have been shown to be safe in small studies. It is difficult to guarantee that an oil is refined to remove all traces of peanut protein, which is the trigger for allergic reactions.

Some restaurants use peanut oil for cooking, and peanut proteins may leach into the oil. Therefore, avoidance of peanut oil is advised. Little research has been done to prove the safety of other nut oils, so avoidance is advised.

Q 11: What does cross reactivity mean?

Cross reactivity means that a similar protein is present in several foods, then a person may have allergic reactions to any food containing that protein. Some people may be allergic to more than one protein in more than one food, so they may be allergic to several foods. An example of cross reactivity includes similar proteins present in cashew and pistachio nut.

It may be difficult to predict whether a person will be allergic to one unique protein allergen present in one food only, or several similar cross reactive proteins present in multiple foods. It is not possible to reliably predict the likelihood of allergy to seed or nut like foods without allergy testing to that food.

Content updated April 2024

For more information go to www.allergy.org.au/patients/food-allergy

To support allergy and immunology research go to www.allergyimmunology.org.au/donate