How To Introduce Allergens To Your Baby

It is important to introduce allergens to your baby when they are weaning onto solids to find out if they have any allergies. Food allergies are somewhat common in babies, and around 5% of children under the age of five will have at least one form. But with the right treatment and management, you can minimise their impact on your child’s life. 

In this article, we’ll talk about food allergies and why they occur, the importance of introducing allergens, what to do if your baby has an allergic reaction and diagnosing and treating allergies. 

What Is A Food Allergy?

A food allergy is a condition which occurs when your child’s immune system has an adverse response to a protein in a particular food. This leads to an inflammatory reaction that can take on a number of different forms, from skin rashes and upset stomachs to more severe reactions such as anaphylaxis. Sometimes, babies will grow out of food allergies – many children grow out of milk allergies by the time they are five – but some allergies will stay with them for life. 

What Are The 14 Major Allergens?

There are 14 common food allergens that need to be declared by food businesses by law. 

They are:

  • Celery (and celeriac)
  • Cereals containing gluten (oats and barley)
  • Crustaceans (prawns, lobsters, and crabs)
  • Eggs
  • Fish
  • Lupin
  • Milk
  • Molluscs (oysters and mussels)
  • Mustard
  • Peanuts
  • Sesame
  • Soybeans
  • Sulphur dioxide and sulphites (if the concentration is more than ten parts per million)
  • Tree nuts (walnuts, hazelnuts, pecans, pistachios, macadamia nuts, cashews, Brazil nuts and almonds)

While food allergies can appear for any foods the 14 listed are a starting point when thinking about potential triggers for your child. The most common to appear in young children are:

  • Eggs
  • Milk
  • Peanuts

Food Allergy Symptoms

Generally speaking, you will notice an allergic reaction in your child within a matter of minutes. Symptoms can include:

  • An itchy red rash
  • Coughing and wheezing
  • Sneezing
  • A blocked or runny nose
  • Itchy, red, or watery eyes

Other food allergies, such as milk allergy, can cause digestive issues such as diarrhoea, wind, or constipation. For the most part, food allergies in babies produce mild symptoms, but sometimes a severe reaction can take place. This is called anaphylaxis, or anaphylactic shock, which means that your baby may be struggling to breathe, wheezing, or losing consciousness. If this occurs, you need to call an ambulance immediately as it is a medical emergency. For more information on what to do if your baby is having a severe allergic reaction, please follow these steps

Introducing Allergens To Your Baby

It is generally advised that you start introducing solid foods to your baby’s diet alongside breastfeeding or formula feeding at around 4 to 6 months. Introducing allergens at this point minimises the risk of them developing an allergy. It will also identify any allergies early on.

Pick one allergen (cow’s milk is recommended) to start with and use a very small amount at first. Use less than half a teaspoon, to begin with, and then increase the amount after a few days. If there is no reaction, you can safely include it once or twice a week in their regular diet. Eggs are the next common allergen to try. A plain omelette could be the easiest bet, but you could also try including eggs in foods like meatballs and potato cakes if they don’t like the texture. Next, it’s peanuts. Try mixing a little salt-free smooth peanut butter with porridge or yoghurt. 

Only try allergens when your baby is healthy and when their skin is in good condition so that you can easily identify any reactions. It is important to remember that there are two types of allergic reactions:  IgE mediated allergic reactions and Non-IgE mediated allergic reactions.

IgE mediated allergic reactions will occur quickly, generally within a couple of minutes. Non-IgE mediated allergic reactions can take a couple of days to appear, which is why it is important to make sure that you pace the allergen samples carefully and that you monitor the results closely. 

What Should You Do If Your Baby Has An Allergic Reaction?

If your baby has a mild allergic reaction to any of the foods that you have been introducing them to, then you should immediately stop giving them that food. Most mild symptoms will go away fairly quickly, and if they don’t, then you should contact your pharmacist or GP for treatment to alleviate symptoms more quickly. However, if they have a severe reaction such as anaphylaxis, then you need to seek urgent medical attention. If you think that they have had an allergic reaction, you can contact a paediatrician for food allergy testing.

Food Allergy Testing

If your baby is showing signs of a food allergy, it is very important that you get them tested. Seek advice from your GP or from a paediatrician to find out exactly what the root cause of this allergic reaction is. They will be able to find out whether it is a food allergy. Once your baby has been examined, and the paediatrician has gone through their medical history, they may recommend further testing. 

A common food allergy test is the skin prick test, where a small amount of the allergen is placed on the baby’s arm and scratched. If the skin reacts, then there is an allergy. A blood test can be more specific to determine what the body is reacting to in the case of an IgE-mediated reaction. 

There is also the food elimination test, where the suspected allergen is removed from the baby’s diet, and their health is carefully monitored. A skin patch test (where a small amount of the allergen is placed on a patch for the baby to wear for 48 hours) can be a great way to test for a non-IgE mediated reaction as those symptoms take longer to appear.

Food Allergy Treatment

Sadly, there is no cure for food allergies, but there are a lot of ways that we can treat and manage food allergies. As a parent, you can make sure that you are avoiding triggers, stocking up on EpiPens (which is particularly important if your baby has a nut allergy), and trying immunotherapy. Introducing solid foods into your baby’s diet at 4-6 months – including allergens – will help to prevent food allergies from forming. 

At Children’s Allergy Doctors, we work closely with parents to create a detailed plan of action. We can provide you with helpful information on how to prepare for food allergies, what you should avoid, and what to do in case your baby has an allergic reaction. This will help you to ensure that your child can live an unhindered life that is not defined by their allergy. The more you know, the better you will be able to help your child handle their allergies.

If you are concerned that your baby may have a food allergy, please contact us today to seek a diagnosis. You can book an appointment through our website, email us at or call us on 0203 146 7721.


What parents say:

“She is very kind, very informative about the whole process through the allergies of my baby. Very supportive and had answered all my questions. Feeling more confident about feeding my baby now. Recommended 100%”


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