Types of tree nut allergy

Tree nuts include almonds, Brazil nuts, cashew nuts, hazelnuts, walnuts, pecans, pistachios and macadamia nuts.

 

There are two types of tree nut allergy. The first type is known as a primary food allergy. This is where a person becomes allergic to the nut through direct contact. Although the severity of the allergy can vary, this type of allergy has the potential to cause a severe, life-threatening allergic reaction (anaphylaxis).

The second type of allergy to tree nuts is known as a secondary food allergy. This can happen when a person is initially allergic to tree pollen, and then begins reacting to tree nuts. This happens because of a process called cross-reactivity – where proteins found in pollen are similar to proteins found in tree nuts. Secondary food allergy reactions are usually mild, and often include itching or swelling in the mouth. The condition is known as pollen food syndrome. The most common tree nuts to cause symptoms of pollen food syndrome are hazelnuts, almonds, walnuts and Brazil nuts. For more information, see the link at the end of this article to read our pollen food syndrome factsheet.

 

It is important you know which of the two types of tree nut allergy affects you. Discuss this with your GP or allergy specialist.

Where are tree nuts commonly used?

If you are allergic to tree nuts, you must exclude them from your diet. Tree nuts can be used in many different foods and dishes, so make sure you always read food labels carefully and question staff in restaurants, takeaways and other catering establishments.

Tree nuts are commonly found in
  • right_arrow_orange_icon Cakes
  • right_arrow_orange_icon Breads
  • right_arrow_orange_icon Biscuits
  • right_arrow_orange_icon Muesli
  • right_arrow_orange_icon Breakfast cereals
  • right_arrow_orange_icon Ceral bars
  • right_arrow_orange_icon Confectionery (such as chocolates and snack bars)
  • right_arrow_orange_icon Ice cream
  • right_arrow_orange_icon Many types of Asian cuisines
  • right_arrow_orange_icon Salads and salad dressings
  • right_arrow_orange_icon Vegetarian dishes (such as nut loaf or nut roast)
  • right_arrow_orange_icon Vegan alternatives
  • right_arrow_orange_icon Gluten-free alternatives

Tree nut oils should be avoided if you are allergic to the tree nut. Tree nut oils can be used for frying, baking and to make salad dressings.

 

Tree nut oils may also be found in medicines, toiletries and cosmetics. It is difficult to determine the level of risk posed by these products, so we advise caution and avoiding them completely. In cosmetics they are labelled in Latin. For more information, see the link at the end of this article to read our cosmetics, personal care products and medicines factsheet.

Almonds

Almonds are used to make marzipan, frangipane, praline and cakes, such as Bakewell tart. Almonds are often used in curry dishes and in some naan bread recipes, such as Peshwari naan.  Almond “milk”, ground almonds, almond flour, almond powder and almond extract are all made from almonds. Almond flour is commonly used as a gluten-free alternative in gluten-free products sold in cafes and bakeries.

 

Almond essence is a very strong-smelling clear liquid, again made from almonds, and is sometimes added into cakes and biscuits. Almond flavouring is sometimes made from almonds, but not always. With this uncertainty we believe it is best to be cautious and avoid almond flavourings altogether if you are allergic to almonds.

 

Almonds are used to make some liqueurs, such as some brands of Amaretto. If in doubt about any liqueur, contact the manufacturer (or visit their website) to check for almond content. Almond oil can be used in confectionery and pastries. It may also be used for shallow frying fish.

 

Almond ingredients can be found in cosmetic products such as creams, soaps, shampoos, hair conditioners and massage oils. In cosmetics, you need to look for the Latin names Prunus amygdalus amara (bitter almond) and Prunus amygdalus dulcis (sweet almond).

Brazil nuts

Brazil nuts are not as commonly used in confectionery as some other tree nuts, but are used in some chocolates, e.g. Cadbury Roses.

 

Brazil nut butter can be found in most supermarkets and health food shops.

 

Brazil nut oil can be used to make salad oils and dressings.

 

In cosmetics, you need to look for the Latin name Bertholletia excelsa.

Cashew nuts

Cashew nuts are frequently used to make pesto sauce (which is traditionally made from pine nuts). They are also often used in Asian cooking, particularly in sauces.
Cashew nut butter and cashew “milk” can be found in some supermarkets and health food shops.

 

As far as we are aware, the oil derived from cashew nuts is not used in foods made and sold in the UK. However, it is best to be on your guard in case this should change.

 

In cosmetics, you need to look for the Latin name Anacardium occidentale.

Hazelnuts

Hazelnuts, also known as filberts or cob nuts, are often used in chocolate spreads, praline, nougat and confectionery.

 

Hazelnut butter and hazelnut “milk” can be found in some supermarkets and health food shops.

 

In Europe, hazelnuts are made into liqueurs, such as Frangelico Hazelnut Liqueur.

 

Hazelnut oil can be used for baking or salad dressings. It may also be used for shallow frying fish.

 

In cosmetics, you need to look for the Latin name Corylus rostrata. Variations may include Corylus americana or Corylus avellana.

Hazelnuts may be used in dishes such as:
  • right_arrow_orange_icon Dukkah – a spicy dry dip. It can also be used as a seasoning mix.
  • right_arrow_orange_icon Za’atar – a mixture of sesame seeds, herbs and spices to which hazelnuts are sometimes added. It is mixed with oil and sprinkled over a variety of items including salads, soups and white cheese.

Walnuts

Walnuts may be found in salads, such as the Waldorf salad. Walnuts can also be pickled.

 

Certain cakes often contain walnuts, such as carrot cake and banana bread.

 

Walnut butter can be found in some supermarkets and health food shops.

 

Walnuts are used in some brands of Worcester sauce.

 

Walnut oil can be used for salad oils and dressings or drizzled onto grilled food.

 

In cosmetics, you need to look out for the Latin names Juglans regia and Juglans nigra.

Pecans

Pecans can be found in desserts and confectionery products, such as pecan pie and pecan praline.

 

Pecan butter can be found in some supermarkets and health food shops.

 

Pecan oil can be used for frying and baking. It can also be used as a salad dressing.

 

In cosmetics, you need to look out for the Latin name Carya illinoinensis.

Pistachios

Pistachios can be found in desserts and confectionery, such as chocolates and puddings.

 

Pistachio butter, spread or cream can be found in some supermarkets and health food shops.

 

Pistachios are commonly used in Middle Eastern foods, particularly desserts such as baklava and Turkish delight.

 

Pistachio oil can be used as a salad dressing.

 

In cosmetics, you need to look for the Latin name Pistacia vera. Variations may include Pistacia manshurica.

Macadamia nuts

The macadamia nut, also known as the Queensland nut, can be found in desserts and confectionery products, such as chocolates.

 

Macadamia nut butter or spread can be found in some supermarkets and health food shops.

 

Macadamia nut oil can be used for baking, salad dressings or drizzled onto grilled food.

 

In cosmetics, you need to look for the Latin name Macadamia ternifolia. Variations may include Macadamia integrifolia.

Reviewers

The content of this article has been peer-reviewed by Dr Gary Stiefel, Consultant in Paediatric Allergy, University Hospitals of Leicester NHS Trust, and Rachel de Boer, Principal Paediatric Dietitian, Evelina Children’s Hospital London.

 

Disclosures

 

Dr Stiefel is a principal investigator for a study funded by Aimmune on peanut immunotherapy and has provided advice for Aimmune.

 

Disclaimer

 

The information provided in this article is given in good faith. Every effort is taken to ensure accuracy. All patients are different, and specific cases need specific advice. There is no substitute for good medical advice provided by a medical professional.

 

Publication Date: April 2022
Review Date: April 2025