Food Allergies in Babies: All you need to know

Dr Sophie Niedermaier

This week is Allergy Awareness Week and we have put some useful information together for you. Allergic reactions can be a scary event for parents but, luckily, it is quite rare.

Food allergies affect around 7 out of 100 babies in the UK with 1 in 40 developing peanut allergy and 1 in 20 developing egg allergy. They usually show in different ways and the symptoms depend on the part of the body, where the allergy occurs. This can happen on the skin, in the gut, the lungs or as a reaction of the whole body (systemic reaction)

What are the symptoms of food allergies?
Symptoms include (but don’t exhaust)


  • Hives, swelling or redness
  • Itching
  • Eczema


  • Swelling of the tongue and the lips
  • Diarrhoea or constipation
  • Nausea and vomiting
  • Tummy pain
  • Reflux
  • Blood or mucus in the stool


  • Runny nose, sneezing
  • Cough
  • Chest tightness and wheezing

Systemic (anaphylaxis):

  • A combination of the above mentioned symptoms
  • Low blood pressure causing dizziness or fainting
  • High heart rate

If you think your baby might have an allergic reaction to food, it is best to stop giving this food and consult a doctor immediately. If your little one shows signs of anaphylaxis, call 999.

Different types of food allergies:

There are two types of food allergies, one, which starts immediately after having eaten the allergenic food (immediate or IgE-mediated type) and one, which starts with a delay (delayed type or non-IgE-mediated type)

  • Immediate or IgE-mediated allergy: It is caused by specific antibodies built by the body against a specific food. The reaction starts within the first two hours after eating the specific food, usually within minutes after the allergen has entered the body. The reaction is usually very acute and can vary between showing hives, over vomiting and diarrhoea to a severe systemic reaction.
    There are specific skin and blood tests, which can test if the specific antibodies are present in the body. The diagnosis can most of the times be made based on the history.
  • Delayed or Non-IgE -mediated allergy: This type of allergy is caused by other immune cells in the body and occurs between 2 hours up to 3 days after a food has been eaten. Symptoms usually include diarrhoea or constipation, reflux, eczema or wheezing cough.
    It is more difficult to diagnose this kind of allergy, as symptoms can be nonspecific and the association with the ingested food is not always clear. There aren’t any blood or skin tests for this allergy. Your doctor will probably recommend to cut out a specific food from the diet for two weeks and watch out for a change in symptoms.

Common food allergens:

There are 8 different foods, which cause almost 90% of all food allergies. These foods are:

  • Cows' milk
  • Eggs
  • Gluten-containing foods, such as wheat, barley and rye
  • Nuts and peanuts
  • Seeds
  • Soya
  • Shellfish
  • Fish

It is recommended to introduce these allergens to all babies after the age of 6 months. Early introduction of peanuts and eggs has been shown to reduce the risk of developing an allergy, especially in babies with a high risk of developing one, for example because they have eczema.

Introduce only one allergen at a time over the course of three days and look out for any reactions. If you haven’t observed any symptoms, you can move on to the next allergen. Make sure you offer the different foods to your baby on a regular basis, so they can get used to them. If your baby has eczema or if there are severe food allergies in your family, talk to your health professional before introducing allergens to get some reassurance.

What do I do if I think my baby has a food allergy?

The first thing you should do is consult your GP or paediatrician. They will most likely talk to you about avoiding the specific food and refer you to an allergy specialist. This specialist will take a detailed history and might perform a skin or a blood test.

Once an allergy has been confirmed, keep avoiding the food. A dietitian can help with replacing the vitamins and micronutrients of this specific food by other food groups.

Will my child outgrow their allergy?

Most babies grow out of their allergies, depending on the severity and the type of food they are allergic to:

60 to 80 percent of children allergic to milk, egg or soy will be able to eat these foods by the time they are 16 years old. Your doctor will most likely recommend to introduce these foods in processed form first, for example baked. If children can tolerate allergens in this form, it is very likely that they will be able to eat plain egg or milk in the future.

Children with allergies to nuts, peanuts, fish or shellfish are less likely to outgrow their allergies. For example, about 1 out of 5 children outgrows their peanut allergy.

Other factors, which mean a child is likely to outgrow their allergy include earlier age of the first allergic reaction, having only mild to moderate symptoms, allergy to just one food and having eczema as only symptom of food allergy.


Dr. Sophie Niedermaier-Patramani