Allergies are different from intolerances. Symptoms of an allergy happen when a person’s immune system overreacts to seemingly harmless things that most other people would not react to, such as animals, a particular food or pollen. In some cases, the immune response can be so serious that it becomes life-threatening (anaphylaxis). Allergic symptoms happen quickly after exposure to the allergen; in the case of food, it usually happens within 10-20 minutes after eating the food, but it can happen immediately or up to two hours later.


Symptoms of food allergy can include:

  • Tingling or swelling of the lips, mouth, tongue and/or throat
  • Vomiting or nausea
  • Diarrhoea
  • Abdominal pain/discomfort
  • A red, raised, itchy rash
  • Tightness of the chest/wheezing
  • Coughing continually
  • Hoarseness/loss of or croaky voice
  • Drop in blood pressure, dizziness or feeling faint

Depending on the severity of the allergy, the problem can range from being mildly uncomfortable to having a severe impact on daily life. If you suspect your child has a food allergy, you should consult your doctor before making any dietary adjustments. Do not let your child eat the suspect food again without medical advice.

Allergies commonly run in families, and these are referred to as ‘atopic’. Such families have higher than average incidences of asthma, eczema, hayfever and food allergies.

Visiting your GP

Allergy UK has the following advice when it comes to helping your doctor diagnose your child: try to think of when your child started having symptoms and note the date, time of year and how long they lasted. Think back to your child's diet and what activities they were doing, and try to record all these details so the doctor can get a clear picture of what has happened. Some doctors may give you a symptom diary to fill in, where you can record all this information, as these clues can lead to a quicker diagnosis. For more information, read the childhood food allergy information published by Allergy UK.

More like this

Once your GP has completed their assessment, they will recommend the next course of action – this may be referral to a specialist, an allergy test or an elimination diet. If your child needs either of the latter approaches, it is important that they be performed by an appropriate healthcare professional with the competencies to select, perform and interpret the results and/or guide you through any dietary changes. Speak to your GP or a registered dietician for advice.

Vegan alternative nut milk in glass bottles on dark background. Healthy food background. Healthy vegan food concept.

Allergies and food groups

Foods can be grouped into problem families that might not seem immediately obvious. For instance, some foods have similar proteins to pollen, such as kiwi, apples, potatoes and soy beans. This means that if someone has hay fever, they may react to these foods due to a cross-reaction of similar compounds, referred to as pollen food syndrome or oral allergy syndrome. This can make diagnosis of what’s causing the problem difficult unless symptoms are very obvious.

Milk allergy

Cow’s milk allergy is one of the most common to affect babies and young children, and probably one of the most awkward. Thankfully, by the time most children start school, they should have outgrown their milk allergy, although for a small number the allergy stays with them into adulthood. Any immediate reactions to milk requires medical action, as it can be severe. Going dairy-free can mean making changes for the whole family. This may sound daunting, but read our spotlight on dairy-free diets for advice on ingredients and how to make dairy-free swaps.

Egg allergy

An egg allergy is more common in children than adults and can cause severe symptoms, but thankfully most children grow out of it. A child’s allergy to egg may be quite specific, such as to raw egg only or to all forms of egg (cooked, loosely cooked and raw) – this emphasises the importance of seeing an allergy specialist so that unnecessary foods or ingredients are not eliminated from the diet.

Little boy opening up peanuts to eat in a restaurant

Nut allergy

An allergy such as a peanut or tree nut allergy, can be severe and lifelong. If your child is living with a peanut and/or tree nut allergy, our spotlight on nut-free diets gives an overview of nut allergies, including foods to avoid, how to read labels and suggested recipes to try. If you suspect your child has a peanut or tree nut allergy, you should consult your GP immediately.

Possible strategies

Your GP or healthcare professional will advise on the best course of action, which may include:

  • Total avoidance of the allergen
  • Antihistamines to use when the reaction is mild
  • Adrenaline, such as the EpiPen and Jext – brand names of adrenaline auto-injector devices available in the UK. These are used for severe reactions and can be lifesaving for inadvertent exposure to food allergens
  • In a number of instances (such as hay fever, asthma and eczema) you can try making changes to your diet and lifestyle to reduce the overall allergenic 'load' placed on the immune system. This may help to improve overall quality of life, although you would still need to avoid the food to which you are allergic

Have you had a child diagnosed with a food allergy? Share your experiences below...

This article was last reviewed by Allergy UK on 2 February 2024.


All health content on is provided for general information only, and should not be treated as a substitute for the medical advice of your own doctor or any other healthcare professional. If you have any concerns about your general health, you should contact your local healthcare provider. See our website terms and conditions for more information.

Comments, questions and tips

Choose the type of message you'd like to post

Choose the type of message you'd like to post