Food allergies in babies

Food allergies happen when our immune systems mistake certain foods as a threat which triggers a defence response, causing all the classic allergy symptoms (like rashes or swelling)¹.

Food allergies are more common in babies than adults and affect around 5-8% of children in early childhood². Luckily, many outgrow their allergies as they get older.

Here’s our guide on how to safely introduce common allergens when weaning your baby onto solid foods, how to spot common infant food allergy symptoms, and what to do if your baby has an allergic reaction to food.

As you begin your weaning journey and introduce your baby to solid foods for the first time, it’s important to look out for any infant food allergy symptoms.

The most common, and immediate, signs of food allergies in babies are³:

• Sneezing
• A blocked or runny nose
• Watery, red or itchy eyes
• Coughing, wheezing or worse asthma symptoms
• An itchy rash or worse eczema symptoms
• Diarrhoea or vomiting
• Tummy pain or constipation

Infant food allergy symptoms can be mild, moderate or severe and can sometimes cause anaphylaxis (difficulty breathing), which requires immediate medical attention³.

That’s why it’s so important to look out for signs of food allergies when weaning, so you can get a proper diagnosis and support with treatment and management.

Your baby has a slightly higher chance of having a food allergy if you or another close family member has allergies, asthma or eczema¹. But just because someone in the family has allergies doesn’t mean your baby will develop them. And even if there’s no history of allergies in your family, that’s not to say your child won’t develop one.

In reality, there’s no foolproof way to tell until you introduce common allergens into your baby’s diet.

It’s normal for expectant mums to wonder whether their diet during pregnancy can affect whether their baby will develop a food allergy. But when you’re pregnant or breastfeeding, you don’t have to avoid any allergens unless you’re allergic to them yourself (your baby won’t develop a newborn egg allergy through your milk, for example)³.

Experts advise sticking to a healthy, balanced diet and looking after your general health while you’re pregnant.

Some foods are more likely to cause infant food allergy symptoms (like food allergy rashes) than others. Common food allergy foods include³:

• Cow’s milk
• Eggs (always choose eggs with a Red Lion stamp)
• Foods containing gluten (e.g. wheat, barley and rye)
• Nuts and peanuts (serve finely ground or as a nut butter to prevent choking)
• Beans, lentils and peas
• Sesame and other seeds (make sure these are finely ground)
• Soya
• Fish and shellfish (always serve fully cooked)
• Celery
• Mustard
• Sulphur dioxide (a preservative found in some fruit juices and dried fruits)

Your baby is more likely to develop an allergy to foods like peanuts, dairy and eggs if you delay introducing them to their diet⁴. That’s why it’s a good idea to start introducing common allergens as soon as possible after you start weaning at around 6 months.

It’s normal to feel a little anxious about introducing foods that may cause a reaction. Try following these tips to make the process a little easier⁵:

• Introduce one allergen at a time to make it easier to tell what’s causing any reactions.
• Only introduce possible food allergy foods when your baby’s feeling well and doesn’t have any other symptoms (like a cold, for example).
• Keep a weaning diary to help you keep track of your baby’s reactions to different foods.
• If you introduce your baby to nuts, be sure to do so in ground format or in a spread until they reach 5 years of age, as they can be a choking hazard. 

An allergy to eggs is one of the most common childhood allergies, affecting around 1-2% of children under five years old in the UK⁶.

If you’re baby has an egg allergy, you’ll likely notice a food allergy rash, swelling around the mouth, and vomiting when you first introduce egg into their diet. Most of the time, this reaction is fairly mild, but rarely it can develop into anaphylaxis and need medical attention straight away⁷.

Your GP will be able to confirm whether your baby has an egg allergy. They’ll probably advise that you avoid feeding foods containing eggs for 1-2 years (most children outgrow their egg allergy after this time).⁷

Around 1 in 50 children in the UK will develop a peanut allergy, which is often lifelong (although 1 in 5 children will outgrow their peanut allergy by the time they turn 10)⁸.

Peanuts are technically a legume, so your baby can have a peanut allergy and not react to tree nuts (almonds, Brazil nuts, cashews, hazel nuts, macadamia, pecan, pistachios and walnuts)⁸. It’s possible to be allergic to peanuts on their own or a combination of tree nuts and peanuts.

Signs and symptoms of a peanut allergy usually appear within minutes of your baby eating them, although they can happen up to an hour afterwards. Mild symptoms include an itchy mouth, swelling and a food allergy rash. A peanut allergy can also cause anaphylaxis, which requires immediate medical attention⁸.

If you think your baby might have a peanut allergy, talk to your GP. They’ll be able to provide an official diagnosis and help you understand how to manage it.

Cow’s milk allergy is one of the most common food allergies in children, affecting around 7% of babies younger than one (although most outgrow their cow’s milk allergy)⁹.

If you formula-feed your baby, you might have noticed a newborn milk allergy already. Symptoms of a baby or newborn allergic reaction to milk can be anywhere from mild to severe, including a food allergy rash, tummy issues or breathing problems⁹.

If your baby is diagnosed with an infant or newborn milk allergy, you might need to use cow’s milk alternatives when weaning⁹.

It’s important to note that a cow’s milk allergy is not the same as an infant dairy allergy, where your baby is allergic to all dairy products. Infant dairy allergy is fairly uncommon, but speak to your GP or health visitor if you have any concerns⁹. 

For many parents, the diagnosis of their baby’s food allergy can come as quite a relief. But it can also be the beginning of a lifelong journey – one which requires extra thought, care and planning on a daily basis. 

But having a good understanding of your child’s allergy can make it easier to manage. Make sure that you provide anybody who cares for them with the information they need about their allergy, and details of the foods they can and can’t eat.

Remember that spreading awareness around the issue of allergies is a good thing. Talking to other parents will not only help put your mind at ease but also help others to understand what the impact of food allergies can be on children.

Depending on the food your child is allergic to, avoiding it may mean that they’re at risk of missing out on key nutrients. It’s a good idea to seek support from a dietitian to ensure that your baby gets the full range of nourishment they need for healthy growth and development ³.

If your baby is diagnosed with a food allergy, you’ll need to avoid giving them any foods containing their allergen. You can do this by paying special attention to food labels.

There are strict guidelines about how manufacturers label prepackaged foods to make allergens easy to spot. They must include a list of ingredients and have common allergens listed in bold.

Sometimes ingredients in foods change, so it’s important to check the label every time, even if you’ve fed your baby a particular food before with no issues¹⁰.

Some manufacturers might also use ‘precautionary labelling’ when a food ‘may contain traces of’ a common allergen if they’re used in the same factory (e.g. nuts or gluten). Depending on how severe your baby’s food allergy is, you may or may not want to avoid these foods. Speak to your GP or a registered dietician for more advice¹⁰.

There are currently no established ways to treat infant food allergies other than avoiding foods that contain the allergen. But there are ways to manage infant food allergy symptoms¹.

For mild allergic reactions (e.g. infant allergic reaction rash), your GP might recommend using antihistamines. You might also be given an adrenaline auto-injector (or EpiPen) for use in emergencies such as anaphylaxis¹.

When your baby is diagnosed with an allergy, you’ll be given an allergy management plan explaining how to avoid allergens and what to do if you spot any infant food allergy symptoms.