Tree Nut Allergy

Who is at risk of Tree Nut allergy?

Those with an existing peanut allergy have an increased likelihood of around 30-40% of developing a tree nut allergy as similar proteins are found in both types of nuts. Having an existing tree nut allergy does not automatically mean an allergy to peanut although it is not uncommon to be allergic to both some tree nuts and peanut. Infants with eczema and/or an egg allergy are more likely to develop other food allergies.

More about Tree Nuts:

Tree nuts as the name suggests, are grown on trees. It is possible to be allergic to one or more types of tree nuts as they have similar proteins. This is referred to as cross-reactivity. People with an allergy to tree nuts also have an increased risk of sesame allergy due to cross reactivity.

It is important to know that tree nuts are from a different family to peanut, which is a legume. Having a tree nut allergy does not automatically mean an allergy to peanut.

Reactions to tree nuts can also be triggered in people who have pollen food syndrome, also referred to as oral allergy syndrome. when there is a hypersensitivity reaction to fruit, vegetables and nuts when cross reacting with certain aero allergens (e.g birch pollen). Symptoms are typically mild causing irritant symptoms such as itching of the mouth, lips and throat when eaten in their raw form. Anaphylaxis can occur but is uncommon.

There are eight tree nuts in the tree nut family including:

• Almonds
• Brazil nuts
• Cashews
• Hazelnuts
• Macadamia
• Pecan
• Pistachios
• Shea nuts
• Walnuts

Shea nuts are also a tree-nut and are being increasingly used in confectionary in the form of butter or oil. Due to the processing of foods The amount of protein contained is small and the risk of a reaction is very low, however some people with a tree-nut allergy may choose to avoid it.

What are the signs and symptoms of an allergic reaction to treenuts?

Signs and symptoms usually occur within minutes of contact with tree nuts but can also occur up to two hours later. Most allergic reactions to tree nuts are mild but for some people they can also be moderate or severe.  Anaphylaxis (pronounced ana-fil-laxis) is the most severe form of allergic reaction which can be life threatening.

Please see our Factsheet on anaphylaxis and severe allergic reactions for more information and guidance on what to do when these severe symptoms occur.

Types of allergic reaction

It is commonly misunderstood that food allergic reactions become more severe each time they happen. Reactions are unpredictable and there is no reliable way of knowing how an individual may react on future exposures, meaning that being prepared by knowing the signs and symptoms, and having an individualised allergy action plan is important. There are several reasons why an allergic reaction may be more severe, including how much nut allergen has been eaten and other factors such as uncontrolled asthma, exercise, and infection. Some people do seem predisposed to more severe reactions with a previous anaphylactic reaction increasing the risk of a further one.

Diagnosing a tree nut allergy

It is important to seek advice from a Healthcare professional if a tree nut allergy is suspected. In the first instance, this will usually be your GP. They may arrange for allergy testing to be carried out or refer you to a specialist allergy service for skin prick testing and/or specific IgE blood testing to tree nuts. These tests help determine if a food allergy is likely although a positive test on its own does not diagnose food allergy.  Allergy tests cannot predict how mild or severe an allergic reaction will be, or when an allergic reaction is likely to happen.

Living with a tree nut allergy

As there is currently no cure for a tree nut allergy the complete avoidance of tree nut(s) and foods which contain tree nuts is an important part of living with a tree nut allergy. Tree nuts are widely used in a variety of foods and are a common ingredient in different types of cooking like Asian, Chinese, Indian, Thai and Vietnamese cuisine. They can also be found in the following foods baked goods, cereals, ice cream and desserts.

• Nut butters (such as almond or cashew)
• Nut milks (such as almond, hazelnut, cashew)
• Biscuits, pastries, and cakes with nuts as ingredients (e.g., chocolate brownies, amaretto biscuits, macaroons, almond croissants, Bakewell tart, carrot cake)
• Nutella (hazelnut)
• Confectionary and chocolate (e.g nougat, Ferrero Rocher, Toblerone, Snickers, Topic, Picnic, selection sweets such as Quality Street, Roses, Celebrations)
• Ice cream (e.g., nut flavoured like pistachio as well as nut toppings)
• Gluten free foods often contain almond meal
• Marzipan
• Food flavourings (almond)
• Pesto (may contain other tree nuts as well as pine nuts)
• Breakfast cereals such as muesli or honey nut cornflakes
• Bread and crackers (speciality breads topped or containing nuts, e.g walnut bread)
• Cereal bars
• Vegetarian food (veggie burgers, nut roasts)
• Mixed nuts and raisins
• Salads with added nuts or nut oils

Reading a food label

Following Brexit, the UK still follows EU legislation regarding the 14 most common allergens (which includes tree nuts and peanut). This means tree nuts must be clearly emphasised in bold or highlighted.

Outside of the EU food labelling laws will be different so it is important to check ingredients carefully, especially where food has been imported from outside of the EU or when eating out whilst on holiday.

 Example of a food label highlighting that it contains a tree nut:

INGREDIENTS: Wholewheat (68%), Dried Fruit (27%) (Raisins, Coconut, Banana {Banana, Coconut Oil, Sugar, Flavouring}, Apple, Hazelnuts), Sugar, Salt, Barley Malt Flavouring, Vitamins & Minerals: Niacin, Iron, Vitamin B6, Vitamin B2 (Riboflavin), Vitamin B1 (Thiamin), Folic Acid, Vitamin B12

Allergy Information

May Contain: Nuts

Precautionary labelling: ‘May contain’ and ‘made in a factory’ statements

Currently there is no law to recommend when these statements should be used on a food product. There is large variation between products, but generally, snacks and dry foods such as cereals, cereal bars, chocolate, biscuits, and nuts are at more risk of cross-contamination with allergens, at source and during manufacturing, than other foods.

It is safest to avoid all foods with a precautionary “may contain” nuts warning.  However, your allergy specialist will be able to give you individually tailored advice to help assess risk and give appropriate management.

Nut oils

Some oils contain nuts and may be a risk to those with a tree nut allergy. They can be split into two categories:

• Refined: These are highly processed which reduces the likelihood of nut proteins remaining in the oil. Therefore, these are unlikely to cause an allergic reaction.
• Unrefined: Examples include: cold pressed or un-processed such as almond and walnut oil. These may contain sufficient amounts of tree-nut proteins to cause an allergic reaction.These should be avoided by people with an allergy to those specific nuts.

It is also important to check the ingredients of vegetable oils as they occasionally can contain traces of tree nuts. If they do it has to be highlighted in the ingredients.

Cross contamination

Cross contamination occurs when a nut free food comes into contact with nut proteins accidentally. This could be in the manufacturing process, storage, or food preparation. Even tiny traces of tree nut proteins can cause an allergic reaction in very tree nut sensitive individuals if they are eaten. At home ensure that all work surfaces and chopping boards are well cleaned using hot, soapy water. Use separate containers for jams, butter etc. especially if you are using peanut butter and always use clean utensils for serving them.

Misleading nut-named foods

Despite having the word ‘nut’ in their name there are many foods that are not from the tree nut family and do not need to be avoided. The following list identifies if they should be avoided if you have a tree nut allergy.

Coconut: Coconut does not need to be avoided; it is a fruit (seed) of a coconut palm tree.

Nutmeg: Nutmeg does not need to be avoided as it is a seed from the nutmeg tree.

Water chestnut: Water chestnuts do not need to be avoided as they are an aquatic vegetable

Chestnuts: Chestnut allergy is considered rare. They are in a different botanical category to tree nuts and peanuts. Most people with a chestnut allergy can tolerate tree nuts and peanuts. Speak with your allergy team if you are unsure. Chestnuts are more commonly seen at Christmas time when roasted at markets

Butternut squash: Butternut squash does not need to be avoided as it is technically a fruit.

Pine nut: Pine nuts are edible seeds from pine trees. Most people with nut allergy do not need to avoid pine nuts.

Eating out

Businesses selling food are required by EU law to provide information on allergens in food. Therefore, don’t be afraid to ask what foods contain, as it is not always clear from menu descriptions. It is important to highlight a tree nut allergy and request that people cooking and handling food are cautious and avoid cross contamination. It is also helpful to telephone places you are planning to visit before you go to make sure they can cater for your dietary needs. Food establishments (cafés, restaurants, market stalls, food trucks) that serve the following types of food (African, Chinese, Indian, Thai and Vietnamese) are likely to use tree nuts and/or peanuts in their food.

When eating away from home with a food allergy, allergy medication should always be taken with you, or on behalf of a child, in case of accidental exposure which commonly happens when eating outside of the home.

Allergy UK is able to provide a translation card service which can be used when travelling or eating out abroad. (These are available in multiple languages at a small cost from Allergy UK’s Helpline (01322 619898)). These cards have English on one side and the translated food allergen(s) in the language required on the other.

They can also be used in the UK as a card written in English with the allergens you need to avoid. This can save a lot of time, and showing the card makes sure the seriousness is understood. These cards are the size of a credit card and can easily be stored in a purse, wallet, or pocket.

Air travel

Many nut allergic people and their families find that air travel, in particular, can provoke anxiety about the possibility of having an allergic reaction on board. The high altitude, close proximity of fellow passengers and the re-circulated cabin air can all contribute to this fear if the cabin crew serves nuts or someone opens a packets of nuts near them.

There are many things that can be done to reduce this risk, such as making sure that hands are washed before eating or putting hands into the mouth; wiping clean the tray table and arm rests with wet wipes; requesting a nut free meal or providing your own food; avoiding airline pillows and blankets; requesting an announcement made asking that other passengers do not consume nuts/nut products, and making sure that all prescribed medication is immediately available to you in the cabin (not stored in the luggage in the hold). Currently, there is no legal requirements from the airline to enforce an announcement and some may refuse to do this. It is important to contact your airline well in advance to alert them of your allergies.

There is limited evidence that nut protein can be circulated in the cabin air and cause a severe reaction and such reactions are very rarely reported in flight. Where research studies have been done it has showed that the nut protein is too heavy to be circulated in this way. It is always advisable to contact the airline before booking or travelling to ask what provision is made to protect the nut allergic person on board so that an informed decision can be made. Don’t forget to contact all airlines if there are connecting flights. See our food allergy and travel Factsheet for further information.

Food allergy alerts

Sometimes processed or pre-packaged foods have to be withdrawn or recalled from food suppliers like supermarkets and shops as there may be a risk to people who have bought or eaten these products. This is because the allergen labelling is missing, wrong or there has been a contamination risk.

These Alerts are available from the Food Standards Agency (FSA) website. It is also possible to subscribe to the FSA’s free email or SMS text message alert system to receive messages when Allergy Alerts are issued. Allergy UK also lists Allergy Alerts that have been made known to them and you can subscribe to its free email Alert system. Contact the Allergy UK Helpline on 01322 619898 for more details.

Nuts and nut-named foods in skincare products and cosmetics

Tree nuts, peanuts or foods with the word ‘nut’ in them can be used in cosmetics such as moisturisers, soaps and shampoo. They can also appear on products with a Latin name. Please see table below to clarify the different names:

• Sweet/bitter almond – Prunus dulcis/Prunus amara
• Brazil – Bertholletia excelsa
• Cashew – Anacardium occidentale
• Hazelnut – Corylus rostrata
• Macadamia – Macadamia ternifolia
• Pecan – Carya Illinoinensis
• Pistachio – Pistacia vera
• Walnut – Juglans regia / nigra
• Shea nut – Butyrospermum Parkii

Nut oils like peanut or almond oil can be used in cosmetics and toiletries and can be a problem to those with an allergy to those foods. The amount of protein allergen that remains in a product after the processing will vary depending on the processes used.

The risk of developing allergic sensitisation to a food via the skin or hair from oils or cosmetics containing nut is not fully understood. Shea Nut, Argan nut, and coconut are commonly used in skin and hair products. Products that come into contact with the skin that contain a food allergen should be avoided in those with a food allergy to that food ingredient.

Shea nuts are also a tree-nut and are used in cosmetics and are being increasingly used in confectionary in the form of butter or oil. Due to the processing of foods, the amount of protein contained is small and the risk of a reaction is very low. However, some people with a tree-nut allergy may choose to avoid it.

Anxiety

Having a food allergy can be very stressful because of the fear of having an allergic reaction and the need to avoid food allergens can be time consuming and expensive when buying ‘free from’ or alternative foods. Feeling anxious about managing your own or child’s allergy is understandable and patient organisations such as Allergy UK are here to provide support, advice and guidance to those living with, or concerned about, allergy.