Nut allergies – all you need to know

Nut allergy symptoms

Signs and symptoms of tree nut allergy vary, some appearing within minutes of coming into contact with the nut while others may present up to an hour or two later. Symptoms may be mild, moderate, sometimes severe and even life-threatening.

The most common mild to moderate symptoms include:

• Blotchy raised or itchy ‘nettle’ rash
• Itchy mouth, tongue or throat
• Swelling of lips, eyes or face
• Runny nose and sneezing
• Vomiting, tummy ache and diarrhoea

Severe symptoms include:

• Difficulty breathing, wheezing or a persistent cough
• Swelling of tongue or throat
• Throat tightness
• Drowsiness

Anaphylaxis is the most severe allergic reaction and can be life-threatening, the advice is that if you think you, or someone you are with, is having an anaphylactic reaction, call for emergency assistance immediately.

Which nuts might I be allergic to?

If you have a nut allergy there are eight tree nuts that you may need to avoid, these are:

• Almonds
• Brazil nuts
• Cashews
• Hazelnuts
• Macadamia nuts
• Pecans
• Pistachios
• Walnuts

An allergy to one tree nut does not mean an allergy to them all, however, there is an increased likelihood of a reaction. Chestnuts are in a different botanical category to the eight tree nuts listed above. That said, some people may be allergic to chestnuts despite safely tolerating other nuts. Both coconut and pine nuts are actually a seed rather than a nut, and the majority of nut-allergic people can eat them, although always check with your GP if you are unsure.

Although peanuts are not included in our list, they do represent the most widespread ‘nut’ allergy. However, peanuts are not actually nuts but a member of the legume (bean) family. Other members of this family include soya beans, lentils and garden peas. It is possible to be allergic to peanuts but not to tree nuts, or vice versa, or even to both.

How do nut allergies develop?

Your chance of being allergic to nuts increases if other family members are allergic. The allergy usually develops during early childhood (under three years) with some children outgrowing their allergy by their fifth birthday. However, some people’s nut and peanut allergy persists for years and into adulthood. If you didn’t develop a nut allergy in childhood that doesn’t mean you will be free of allergy, some people develop the condition later in life.

Whether you should avoid consuming nuts during pregnancy is hotly debated and the current advice is that unless you have a strong history of allergies, or have asthma or eczema in either of the parents’ families, you should be safe to continue eating nuts and peanuts. Some evidence suggests that eating a small amount during pregnancy may actually help prevent allergies developing but you should always check with your GP if unsure.

How to get a diagnosis

It’s very important to get a professional diagnosis of any food allergy. First contact your GP, they will check your symptoms and if appropriate refer you on to a specialist allergy clinic for testing which typically involves skin prick tests or blood tests.

You might find it helpful to keep a food and symptom diary, but don’t cut out foods until you have proper diagnosis as this could cause nutrient deficiencies.

What to do if you have a peanut or nut allergy

After a nut or peanut allergy is confirmed, the first line of treatment is usually to avoid them, as there is no cure.

• When shopping, always read food labels. Find out all of the names for nuts and look out for these on food labels and ingredients lists, e.g. peanuts can also be known as beer nuts, groundnuts and monkey nuts.
• Nut oils are usually refined, but it’s recommended that these are avoided, too, as there may be a trace of nut protein.
• When eating out, food outlets should be able to provide a list of food allergens in their products. It’s best to always notify the staff about any nut or peanut allergy so that they can ensure the food is safe and has not been contaminated with nuts.
• If a label states ‘may contain nuts/peanuts’ it’s safest to avoid this food as it may be contaminated.
• Take care with any foods that are not labelled, or anything suspicious, and if you are unsure whether they contain nuts or nut products it’s best to avoid them.
• It’s worth remembering that some non-foods may contain nut traces, such as tree nut oil soap or shampoo.

Medications: For those with a mild to moderate allergic reaction, antihistamines may be used to relieve symptoms. However, as a food allergy can cause severe and life-threatening reactions, you may be prescribed an adrenaline auto-injector ‘pen’ for use in an emergency. Keep this within easy reach and make family and friends aware that the instructions for use are included on the side of the injector pen.

For more information about food allergies, visit anaphylaxis.org.uk and allergyuk.org

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This article was reviewed on 5 January 2024 by Kerry Torrens

Kerry Torrens BSc. (Hons) PgCert MBANT is a BANT Registered Nutritionist® with a post graduate diploma in Personalised Nutrition & Nutritional Therapy. She is a member of the British Association for Nutrition and Lifestyle Medicine (BANT) and a member of the Guild of Food Writers. Over the last 15 years she has been a contributing author to a number of nutritional and cookery publications including BBC Good Food.

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