Peanut Allergy Factsheet

How common is peanut allergy?

Peanuts are a common cause of food allergy, caused when the immune system reacts to the protein found in peanuts. Peanut allergy affects around 2% (1 in 50) of children in the UK and has been increasing in recent decades. It usually develops in early childhood but, occasionally, can appear in later life. Peanut allergy tends to be persistent and only approximately 1 in 5 children outgrow their allergy, usually by the age of 10(1).

Who is at risk of peanut allergy?

Infants with eczema and/or egg allergy are more likely to develop a peanut allergy (2). It is important to know that peanuts are a legume and from a different family of plants to tree nuts (almonds, Brazil nuts, cashews, hazel nuts, macadamia, pecan, pistachios, and walnuts). A peanut allergy does not automatically mean an allergy to tree nuts.

Approximately 30-40% of children with peanut allergy will have an allergy to at least one tree nut. An allergy to peanuts does also increase the likelihood of an allergy to sesame and lupin. Advice on whether it is safe to have sesame, lupin or tree nuts in the diet should be sought from your GP/ allergy specialist.

Related Resources

The information in this Factsheet has been developed to help you understand more about peanut allergy

Sample image
Food AllergyFactsheets

Tree Nut Allergy Factsheet

The information in this Factsheet has been developed to help you understand more about tree nut allergy. Tree nut allergy...

Prevention of peanut allergy

Research has shown that some infants are at a higher risk of developing a food allergy, including those: with eczema (in particular, early-onset or moderate-severe eczema), or who already have a food allergy themselves. Research has shown that these infants may benefit from the introduction of foods containing egg and peanut from 4 months alongside other complementary foods.

Early introduction is thought to help the immune system tolerate peanut protein. Infants with no eczema or known food allergy can be given food containing peanut from the time that solid food is introduced, at around 6 months, when baby is developmentally ready, but not before 4 months and within the first 12 months of life.

This should be in the form of smooth peanut butter or peanut snacks suitable for babies (never use crunchy peanut butter or whole peanuts due to the risk of choking). Once peanut has been introduced into your child’s diet it is important to continue 1-2 teaspoons, 2-3 times per week to maintain tolerance. (Delaying the introduction of peanut can increase the risk of developing a peanut allergy) so ensure you speak to your health professional as soon as possible. It is safe for pregnant and breastfeeding women to consume peanuts unless they are allergic themselves.

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

Signs and symptoms usually occur within minutes of contact with peanuts, but can also occur up to one hour later. Most allergic reactions are mild but 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.

Mild to moderate symptoms include:

Itchy mouth, tongue and throat

Swelling of lips, around the eyes or face

Red raised itchy rash (often called nettle rash, hives or urticaria)

Vomiting, nausea, abdominal pain and diarrhoea

Runny nose and sneezing

Any one or more of the following symptoms are a sign of a severe allergic reaction (anaphylaxis) and should be treated as a medical emergency. If available, adrenaline should be given without delay and an ambulance called with the call operator informed that it is anaphylaxis.

Severe symptoms of anaphylaxis include:

  • Swelling of the tongue and/or throat
  • Difficulty in swallowing or speaking
  • Change in voice (hoarse voice)
  • Wheeze (whistling noise) or persistent cough
  • Difficult or noisy breathing
  • Dizziness, collapse, loss of consciousness (due to a drop in blood pressure)
  • Pale, floppy, sudden sleepiness in babies.

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

Severity of reactions

It is commonly misunderstood that food allergic reactions become more severe each time they happen, but this is not the case.

Reactions are unpredictable and there is no reliable way of knowing how an individual may react. There are several reasons why an allergic reaction may be more severe, including how much peanut 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.

Diagnosis

It is important to seek advice from a Healthcare professional if a peanut 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 peanut. These tests help to confirm if food allergy is likely and rule out other possible causes.

Allergy tests cannot predict how mild or severe an allergic reaction will be, or when an allergic reaction is likely to happen. Alternative types of allergy testing other than those recommended by a Healthcare professional are not advised as these may be from an unreliable source with no value in diagnosing allergy and could lead to removing food from the diet that does not actually need to be avoided. If you are unsure, call Allergy UK’s Helpline to be signposted to your nearest NHS or Private allergy service.

If you have had cause for concern over peanut allergy and have been avoiding peanuts, it is important not to reintroduce peanuts back into the diet without medical advice.

More about peanuts

Peanuts are grown in areas of the world with warm climates such as America, Asia and Africa. They are grown from seed and grow under the ground.

Different varieties of peanut are produced for different uses (for example, peanuts to be used in peanut butter and peanuts in the shell for roasting). Peanuts are from a family of plants called legumes, the same family as garden peas, lentils, soya beans and chickpeas. Most people will be able to eat other types of legumes without any problems and it is rare for people with a peanut allergy to react to other legumes.

Other members of the legume family that can affect people with peanut allergy is lupin as these seeds share similar proteins with peanuts. Lupin flour and seeds can be used in bread, pastry, and pasta. It is often used in wheat and gluten-free food. Lupin is more commonly used in other European countries, Brazil, and the Middle East.

It is very important to be aware of this and seek medical advice from an allergy specialist if you or your child has ever had a severe reaction to peanut as allergy testing to these other foods may also be needed.

Living with a peanut allergy

As there is currently no cure for peanut allergy, the complete avoidance of peanuts and foods which contain peanuts is important. Peanuts are widely used in a variety of foods and are a common ingredient in different types of cooking like Asian and Indian cuisine. They can also be found in foods like muesli and cereals and cereal bars.

It is important to carefully check the ingredients list on food items (specifically those produced outside of the EU as they are not required to include peanut as a highlighted food allergen). Avoid foods which contain peanut and could be listed under any of the following names:

  • Arachis hypogaea
  • Beer nuts
  • Cacahuete
  • Chinese nuts
  • Earthnuts
  • Groundnuts
  • Goober nut/pea
  • Madelonas
  • Monkey nuts
  • Peanuts

Management of peanut allergy: Medications and allergy action plans

In the case of a severe allergic reaction (anaphylaxis) adrenaline is the medication needed to treat allergic symptoms and should be given as soon as possible after symptoms of anaphylaxis are recognised.

Adrenaline auto–injectors, also known as adrenaline pens, are devices that contain the emergency medicine ‘adrenaline’ that can be given in the case of a severe (anaphylactic) reaction to peanut. If you or your child are prescribed an adrenaline auto-injector it is important that you are shown how to use it by the doctor, nurse, or pharmacist. These devices are available as trainer pens for the type of adrenaline pen that has been prescribed (they all work differently) and are useful for practicing or showing others how to use them (they do not contain a needle or medication).

Expiry dates should be noted, and reminder services are available from some of the adrenaline pen websites. Adrenaline auto-injectors that have been used or due to expire should be replaced immediately. Allergy medication prescribed for a child with a food allergy should be documented on a written allergy action plan for the child’s school or after school clubs or activities. Allergy action plans are individual to the person, listing their food allergies and providing advice on the signs and symptoms of an allergic reaction, as well as instructions on what medication to give and when.

Allergy action plans for children can be downloaded for free from the following website: http://www.bsaci. org/about/ download-paediatric-allergy-action-plans. These action plans need to be completed by a Health professional. Adrenaline auto-injectors should be kept away from bright light and extremes of temperatures, but they should always be with, or easily available to, the food allergic person (for example not in a suitcase in the luggage hold of an aeroplane).

Not all people with food allergy need to have or are prescribed an adrenaline auto- injector. This decision is made by a Health professional (GP/Allergy specialist/ immunologist) on an individual basis and will depend on need, including the severity of previous allergic reactions, age, and distance from medical help.

The Medicines and Healthcare Products Regulatory Agency (MHRA) guidance for the prescribing and use of adrenaline autoinjectors recommends that 2 adrenaline auto-injectors are prescribed for those at risk of anaphylaxis, which patients should always carry. this is particularly important for people who also have allergic asthma because they are at an increased risk of a severe anaphylactic reaction (5). Having well controlled asthma is important especially where food allergy and asthma are combined. This mean recognising when asthma symptoms are worsening, knowing asthma triggers, and avoiding them and knowing how and when to use a preventer and reliever inhaler and spacer, as well as seeing a Health professional for a regular asthma review.

Treatment for peanut allergy

As peanut allergy has the potential to cause severe life-threatening reactions and is relatively common, extensive research has been done to look at new forms of treatment. One method that is available privately in some specialist allergy clinics (but not currently on the NHS) is oral immunotherapy (OIT). This is the process of increasing the tolerance of food allergens that are eaten. The concept is that very small amounts of an allergen (e.g. peanuts) are introduced and the amount gradually increased until a target amount of the food is reached and maintained. This should never be tried without medical supervision at a specialist centre, where currently it remains the subject of active research programmes. Please contact your GP or allergy specialist if you would like more information.

Reading a food label

In the European Union (EU) ingredients lists on food labels must clearly emphasise (for example in bold or highlighted) whether they contain any of the 14 most common allergens, these include peanuts. 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:

INGREDIENTS: Maize, Sugar, Peanuts (7.5%), Barley Malt Flavouring, Molasses, Honey (1%), Salt, Vitamins & Minerals: Niacin, Iron, Vitamin B6, Vitamin B2 (Riboflavin), Vitamin B1 (Thiamin), Folic Acid, Vitamin B12

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 “may contain” peanut warnings. However, your allergy specialist will be able to give you individually tailored advice to help assess risk and give appropriate management. For some people with peanut allergy this level of avoidance may not be necessary after this type of risk assessment.

Peanut oils

Unrefined peanut oil (also called groundnut oil) which is often found in South Asian food may still contain proteins and should be avoided. Refined peanut oil has the protein (the allergen) removed, however it is very difficult to be sure that the oil has been refined enough and therefore it is recommended that this is also avoided. Some medications (including Abidec infant vitamins) contain refined peanut oil and therefore should be avoided.

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 peanut proteins can cause an allergic reaction, in very peanut 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 the following foods are not from the tree nut or peanut families so do not need to be avoided if you have a peanut allergy unless you are also allergic to one of the following foods.

  • Chestnut- is an edible product of a group of trees in the beech family
  • Coconut – the fruit (seed) of a coconut palm tree
  • Water chestnut – aquatic vegetable
  • Nutmeg – seed of the nutmeg tree
  • Butternut Squash – technically a fruit
  • Pine nut – the edible seeds of pine trees

Allergy alerts

Sometimes processed or pre-packaged foods must 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 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

Sometimes tree nuts, peanuts, or foods with the word ‘nut’ in them can be used in cosmetics such as moisturisers, soaps and shampoo.

Cosmetic products must include information on the ingredients in decreasing order of the weight of the ingredient. This enables those looking to avoid a certain ingredient to be able to identify and avoid it. 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. 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 Nut, Argan nut, and coconut are commonly used in skin and hair products.

References

1. Stiefel, G., Anagnostou, K., Boyle, R.J., et al. 2017. BSACI Guideline for the Diagnosis and Management of Peanut and Tree Nut Allergy. Clinical and Experimental Allergy. 47, pp. 719-739.

2. NICE: 2011 The National Institute for Health and Care Excellence (NICE) published a guideline on ‘Food allergy in children and young people’. Free to download at: www.nice.org.uk/guidance/CG116

3. Du Toit, G. et al., 2015. Randomized Trial of Peanut Consumption in Infants at Risk for Peanut Allergy (LEAP). New England Journal of Medicine. 372, pp. 803-813.

4. National Institute of Allergy and Infectious Diseases (NIAID) Addendum Guidelines for the Prevention of Peanut Allergy in the United States Summary for Parents and Caregivers U.S. Department of Health and Human Services. January 2017.

5. Medicines and Healthcare products Regulatory Agency 2017 Adrenaline auto-injectors: updated advice after European review. UK Government.

6. Greenhawt, M. et al. 2013 ‘International study of risk-mitigating factors and in-flight allergic reactions to peanut and tree nut’

7. Stutius L et al. 2009. Characterizing the Relationship Between Peanut and Sesame Allergy in Children. Journal of Allergy and Clinical Immunology 123 (2) DOI:10.1016/j.jaci.2008.12.1057

8. ALLERGY AND GASTROINTESTINAL DISEASE| VOLUME 145, ISSUE 4, P1231-1239, APRIL 01, 2020 Defining challenge-proven coexistent nut and sesame seed allergy: A prospective multicenter European study Helen A. Brough, FRCPCH, PhD August 5, 2021, 11:41 AM