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Food allergies and intolerances

Both food allergies and food intolerances can develop at any time without warning, though it's most common for them to develop in childhood.

A food allergy is when the body's immune system reacts in an abnormal way to certain foods.

Common signs of an allergic reaction

While any allergic reaction can be unpleasant and upsetting, more serious reactions can be dangerous and even life-threatening.

Signs of an allergic reaction include:

  • an itchy sensation inside the mouth, throat or ears
  • raised itchy red skin rash (hives or a 'nettle rash')
  • swelling of the face, around the eyes, lips, tongue and the roof of the mouth
  • anaphylactic shock - the most severe form of allergic reaction which should be treated as an emergency.

Common food allergies

In adults, the foods that most commonly cause an allergic reaction are:

  • some types of fruit such as apples, pears, kiwi fruit and peaches
  • some types of vegetables such as potatoes, carrots, celery and parsnip
  • crustaceans (shellfish), such as crab, lobster and prawns
  • tree nuts, such as walnuts, brazil nuts, almonds and pistachios
  • peanuts
  • fish

You can find more information about the symptoms and treatment of food allergies at the NHS website

Food intolerances are different from allergies.They are caused when the body has difficulty digesting certain types of food. Common symptoms of food intolerances are feelings of tiredness, bloating, diarrhoea  and stomach ache, which can be painful and uncomfortable but are not life-threatening. Symptoms of food intolerance can appear several hours after consuming the food, which can make it difficult to identify which food has caused it.

Common food types which can cause intolerance include:

  • Lactose (found in milk and dairy products)
  • Gluten (found in wheat and other grains) - Coeliac UK provide advice on managing this condition

If you suspect you have a food allergy or intolerance, ask your GP for a checkup. They may want to refer you to an allergy clinic or do some tests to be certain what has caused the reaction.

If you have had a severe allergic reaction to food before, your doctor may give you an 'epi-pen' to carry around with you. This is a pen-shaped device which injects the user with adrenalin, which can stop an allergic reaction or anaphylactic shock (a severe, potentially life-threatening allergic reaction). If you have one of these devices, it's best to let your friends and family know that you carry it, and show them how to use it in the case of an emergency.

When eating out, don't be nervous about quizzing the waiters or chefs about what's in the food. Many food outlets and restaurants now display allergy information.  They should be able to tell you whether the dishes you're ordering contain any of the ingredients you're allergic or intolerant to, and may even offer to prepare your food specially without these ingredients.

At the supermarket check labels carefully - ingredients such as nut oils or wheat proteins (gluten) can turn up in unexpected places. You can save yourself time in the supermarket by checking the manufacturers' websites in advance, so you know what you can and can't buy. Many major supermarkets also offer specialist ranges for people with allergies or intolerances.

If someone else cooks for you, or if you use a food delivery or home meals service, it's important to let them know about your allergies or intolerances, to make sure they don't accidentally give you something that will make you ill.

AllergyUK has information on various allergies including food allergies, and advice on how to cook, shop and eat out for allergy sufferers.

The NHS website has information on diagnosis and treatment of allergies and food intolerances, and what to do in an emergency.

The Anaphylaxis Campaign supports people with this condition.

If you are concerned about an allergy or food intolerance, talk to your GP.

Last updated: 02/07/2021