A food allergy is a rapid and serious response to a certain food. If you have a food allergy, the antibodies in your immune system (the body’s defence system) mistake a food for an ‘invader’ and attack it. The antibodies normally involved in food allergies are called immune system antibodies (IgE). These release inflammatory substances into your body, causing unpleasant side effects.

The symptoms of a food allergy usually occur within minutes of exposure (but sometimes take up to an hour) and may include:

  • Tingling on the lips and tongue.
  • Itching around the mouth.
  • A swollen feeling in the mouth or throat.
  • Streaming eyes or nose.
  • Rashes on the body.
  • Wheezing.
  • Nausea.

In a small number of people a severe reaction called anaphylaxis may occur. Anaphylaxis is an extreme allergic reaction which may occur in adults and children but rarely in babies and infants. It starts with the normal symptoms but progresses further, sometimes causing:

  • Laboured breathing.
  • Extreme swelling in the mouth or throat.
  • Increased pulse rate.
  • Severe gastric or abdominal pain, vomiting or diarrhoea.
  • A sense of impending doom, panic and confusion.
  • Weakness or dizziness caused by a sudden drop in blood pressure.
  • Collapse and unconsciousness or anaphylactic shock.

Most anaphylactic reactions come on rapidly, although symptoms can be delayed by an hour or more after exposure. Anaphylaxis is life-threatening, and immediate action must be taken.

In children, the usual triggers for food allergy are milk, egg, soya and peanuts. In adults, it is usually peanuts, tree nuts, mushrooms, fish and shellfish. Sesame, kiwi fruit and celery are other foods that often trigger food allergies. However, all foods can cause food allergies.

Although no one knows why food allergies develop, you're more at risk of them if you or members of your family have other allergic diseases, such as asthma, eczema or hayfever.

About 6% of young children have food allergies, and about 2% of older children, adolescents and adults have them. Most young children outgrow allergies to milk and egg, but only a few outgrow their peanut allergies. Once sufferers reach adulthood, any food allergies will probably last for life, although some mild allergies, typically to fruit and vegetables, may improve over time.


Allergy UK is the country's leading medical charity dealing with allergy and we are here to help you. We can provide you with up to date information on all aspects of allergy, food intolerance and chemical sensitivity.

If you think that you may have an allergy or an intolerance then our fully trained helpline staff will be able to guide you to the appropriate specialist and provide you with practical advice and support in managing your symptoms.

There is a wealth of allergy information available on this site including many detailed fact sheets and articles written and approved by leading specialists in the field of allergy, as well as detailed allergy videos to help you better understand various aspects of allergy.