Food Allergy

What is a food allergy?

A food allergy is when the body’s immune system reacts unusually to specific foods. Although allergic reactions are often mild, they can be very serious. In the most serious cases, a person has a severe allergic reaction (anaphylaxis), which can be life threatening. Call 999 if you think someone has the symptoms of anaphylaxis, such as: Ask for an ambulance and tell the operator you think the person is having a severe allergic reaction.

Most children that have a food allergy will have experienced eczema during infancy. The worse the child’s eczema and the earlier it started, the more likely they are to have a food allergy. It’s still unknown why people develop allergies to food, although they often have other allergic conditions, such as asthma, hay fever and eczema.

Types of food allergies

Food allergies are divided into 3 types, depending on symptoms and when they occur.

• IgE-mediated food allergy – the most common type, triggered by the immune system producing an antibody called immunoglobulin E (IgE). Symptoms occur a few seconds or minutes after eating. There’s a greater risk of anaphylaxis with this type of allergy.
• Non-IgE-mediated food allergy – these allergic reactions aren’t caused by immunoglobulin E, but by other cells in the immune system. This type of allergy is often difficult to diagnose as symptoms take much longer to develop (up to several hours).
• Mixed IgE and non-IgE-mediated food allergies – some people may experience symptoms from both types.

What are the symptoms of a food allergy?

Normally food allergy symptoms appear within a few minutes of eating the offending food, although they may be delayed by up to a couple of hours. The symptoms are usually those of ‘classic’ allergy, some of which are listed below:

• Gut reactions: Abdominal pain, vomiting, diarrhoea
• Skin reactions: Itching and swelling (rash or nettle rash)
• Respiratory reactions: Runny nose, sneezing, wheeze, cough

At the bottom of this page you will find our downloadable Food and Symptoms Diary. Use this to track your symptoms to discuss with your GP.

How can I manage my food allergy?

You can find a whole host of useful tips on management and avoidance on our relevant Factsheets below but there are 3 key things to be on top of when it comes to managing a food allergy:

1. Identify and avoid the cause (if possible)
2. Recognise the symptoms of an allergic reaction by keeping a food diary
3. Know what to do if it happens again

Treatment for a food allergy

The best way to prevent an allergic reaction is to identify the food that causes the allergy and avoid it. Research is currently looking at ways to desensitise some food allergens, such as peanuts and milk, but this is not an established treatment in the NHS.

• Avoid making any radical changes, such as cutting out dairy products, to your or your child’s diet without first talking to your GP. For some foods, such as milk, you may need to speak to a dietitian before making any changes.
• Antihistamines can help relieve the symptoms of a mild or moderate allergic reaction. A higher dose of antihistamine is often needed to control acute allergic symptoms.
• Adrenaline is an effective treatment for more severe allergic symptoms, such as anaphylaxis.

People with a food allergy are often given a device known as an auto-injector pen, which contains doses of adrenaline that can be used in emergencies.

What are the top 14 food allergens?

There are 14 major food allergens which need to be mentioned (either on a label or through provided information such as menus) when they are used as ingredients in a food product or meal. However you can be allergic to any food substance.

The top 14 food allergens are:

Celery; Cereals containing gluten; Crustaceans; Eggs; Fish; Lupin; Milk; Molluscs; Mustard; Tree Nuts; Peanuts; Sesame seeds; Soya and Sulphur dioxide (sometimes known as sulphites)

Below, we have given a brief overview of some of the most common of the top 14 food allergies. More detailed information can be downloaded at the bottom of the page.

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.

It is important to know that peanuts are a legume and from a different family of plants to tree nuts. A peanut allergy does not automatically mean an allergy to tree nuts although it is not uncommon to be allergic to both peanuts and some tree nuts.

Milk allergy

Cow’s milk (protein) allergy (CMA or CMPA) is one of the most common food allergies to affect babies and young children. Most children will have outgrown their allergy to milk by the time they reach school age (around 5 years of age). In a small number of people who do not outgrow their allergy to cow’s milk it will persist into adulthood. Where this happens people are more likely to experience more severe allergic reactions. Adult onset cow’s milk allergy is very rare and as a result there has been little research carried out about it adult-onset food allergies and why they might happen.

Egg allergy

Egg allergy is much more common in young children than in adults. Most children with egg allergy will outgrow it. This is just one important reason why a child with a food allergy should be seen by an Allergy Specialist. Having an egg allergy can mean being allergic to all forms of egg (well-cooked, loosely cooked and raw) or only to loosely cooked and raw egg. You only need to avoid the forms of egg that you react to.

Examples of these different forms can be found on our Factsheet.

Do please check ingredients to ensure that you are:

• Not excluding foods unnecessarily
• Not eating foods that contain egg by mistake

It is easy to avoid eggs that are served on their own when they look like an egg; however they are often hidden in prepared and manufactured foods so beware.

Food allergy labelling

All pre-packaged food must show a list of ingredients which clearly identifies all the ingredients. There are different regulations for foods that are not pre-packaged and which are prepared on-site in smaller food businesses e.g. a café/sandwich shop/deli. There is still a requirement to provide information on the ingredients and allergen content but how this information is shared is up to the individual business.

They may choose to provide this information in a written form, for example on a chalk board, or they may communicate the information verbally.

Allergy Alerts

Sometimes foods have to be withdrawn or recalled if there is a risk to consumers. This could be because the allergy labelling is missing or incorrect or if there is any other food allergy risk, such as cross contamination.

We are informed by the Food Standards Agency and we alert the public via our website, social media and by sending allergy alert emails to those who have requested them from us.

Sign up here to receive Allergy Alerts

Translation Cards

Translation cards are available from Allergy UK and will ensure others are made aware of your allergy despite any language barriers.

A set of three plastic cards per language are provided, each about the size of a credit card. The cards feature an allergy alert message, an emergency message and a message for use in restaurants to ensure that your food order is free from the particular allergen that causes your reaction.

Find out more about our Translation Cards

Pollen food syndrome

Pollen food syndrome, commonly referred to as oral allergy syndrome, is a hypersensitivity reaction to fruits, vegetables and nuts (often referred to as plant based foods) usually causing mild irritant symptoms such as itching of the mouth, lips and throat itching when eaten in their raw form. The most common presentation of pollen food syndrome is to foods that cross react with birch pollen. This is because a variety of plant food allergens have a similar protein structure to birch pollen.

In Europe, the prevalence of birch pollen sensitisation is estimated to be around 8-16%, and of those, approximately 70% cross react with food sources (pollen food syndrome). Foods include: almond, apple, apricot, carrot, celery, cherry, hazelnut, kiwi, nectarine, peanut, peach, pear, plum, potato, soya and walnut.

The most common reactions in Northern Europe are to apples, hazelnut, and carrots. However, this will vary depending on each individual and their pollen allergies. Avoidance of the food that cause reactions is important, however, there is no need to avoid food that do not cause symptoms. Most of the time, the food only needs to be avoided in raw form as cooking denatures (breaks down) the allergen. For many with pollen food syndrome they can tolerate fruit and vegetables that are well cooked. If you are unsure how to manage symptoms or have symptoms suggestive of pollen food syndrome, speak with a health professional.