Introducing Common Food Allergens to Your Baby

Introducing foods that commonly cause allergic reactions can feel like one of the more nerve-racking parts of weaning. You may find yourself watching every mouthful and wondering what you should look for afterwards.

Current NHS guidance says foods that can trigger allergic reactions can be introduced from around 6 months, alongside other solid foods. The key advice is to introduce them one at a time and in very small amounts so that it is easier to identify a reaction if one occurs.

Once an allergenic food has been introduced and your baby tolerates it, the NHS recommends continuing to offer it as part of their usual diet.

If your baby already has eczema, a diagnosed food allergy, or there is a family history of allergies, eczema, asthma or hay fever, speak to your GP or health visitor before introducing allergenic foods.

Which foods are common allergens for babies?

The NHS lists several foods that can trigger allergic reactions. These include:

cows’ milk
eggs
foods containing gluten, including wheat, barley and rye
nuts and peanuts
seeds, particularly sesame
soya
fish
shellfish

Other foods, including celery, mustard and sulphur dioxide, can also cause allergic reactions.

This does not mean these foods should automatically be avoided. For most babies, they can be introduced as part of weaning from around 6 months.

The form in which you serve them matters, however. Whole nuts should not be given to babies because they are a choking risk. Nuts and peanuts can instead be offered crushed, ground or in a suitable smooth nut butter. Seeds should also be served crushed or ground.

Raw or lightly cooked shellfish should not be given to babies. Follow NHS food safety guidance for eggs too, particularly if they do not carry the British Lion mark.

When should you introduce allergenic foods?

NHS guidance recommends starting solid foods from around 6 months, when your baby is developmentally ready.

Foods that commonly cause allergies can be introduced from this point too. There is generally no need to create a separate later stage of weaning specifically for allergens.

In fact, NHS guidance says evidence suggests that delaying the introduction of peanut and hen’s egg beyond 6 to 12 months may increase the risk of developing an allergy to those foods.

That does not mean you need to rush through every allergen at once.

Introducing them individually gives you a clearer idea of which food may have caused a reaction if symptoms appear.

How to introduce an allergen for the first time

Keep the first introduction simple.

Offer one allergenic food at a time and start with a very small amount, prepared in a form that is suitable and safe for your baby’s stage of weaning.

Try not to introduce several new allergens together in the same meal. If your baby reacts after eating a mixture containing egg, peanut and yoghurt for the first time, it can be difficult to know which ingredient was responsible.

You can instead introduce one allergen and observe how your baby responds.

If it is tolerated, keep that food in your baby’s normal diet rather than treating the first taste as a one-off test.

Introducing egg

Egg can be introduced from around 6 months.

You might offer a small amount of appropriately cooked egg in a texture your baby can manage, such as soft scrambled egg.

NHS guidance notes that eggs without a British Lion stamp should not be served raw or lightly cooked.

Egg is a common allergen, so introduce it separately from other new allergenic foods at first.

If your baby tolerates egg, continue including it in their diet in suitable forms.

Introducing peanuts and nuts

Peanuts and tree nuts can also be introduced from around 6 months.

Never give a baby whole nuts because of the choking risk.

Instead, nuts and peanuts should be served crushed or ground. Smooth nut butter can also be incorporated into suitable foods rather than offered as a thick spoonful.

For example, a small amount of smooth peanut butter could be thinned into a familiar food your baby already eats.

If your baby has eczema, an existing food allergy or a strong family history of allergic conditions, speak to your GP or health visitor before introducing peanuts or other allergens.

Introducing cows’ milk

Cows’ milk can be used in cooking or mixed into food from around 6 months.

However, NHS guidance says it should not replace breast milk or first infant formula as your baby’s main drink before 12 months.

Suitable pasteurised dairy foods, including plain full-fat yoghurt and cheese, can also be offered from around 6 months.

If your baby has already been diagnosed with cows’ milk allergy, follow the feeding advice given by your healthcare team rather than introducing dairy independently.

Introducing wheat and other gluten-containing foods

Foods containing gluten, including wheat, barley and rye, can be introduced from around 6 months.

Depending on your baby’s stage of weaning, this might include suitably prepared foods containing wheat or other gluten-containing grains.

As with other allergens, introduce the food in a small amount and separately from other new allergens initially.

There is no NHS recommendation to routinely delay gluten beyond the normal start of complementary feeding for babies without specific medical advice to do so.

Introducing fish and shellfish

Fish can be introduced from around 6 months in a texture suitable for your baby.

Check carefully for bones before serving.

Shellfish can also be introduced, but the NHS advises that it should not be served raw or lightly cooked.

If fish or shellfish is tolerated, it can continue to form part of a varied diet.

Introducing sesame and other seeds

Sesame is another food that can trigger allergic reactions.

Seeds should be served crushed or ground for babies. Sesame may also appear in foods such as tahini, so check ingredients carefully.

As with peanut butter, thick seed pastes may need to be mixed or thinned into another suitable food so the texture is appropriate for your baby.

Introduce sesame separately the first time so that any reaction is easier to identify.

Introducing soya

Soya can be introduced from around 6 months as part of a baby’s diet.

It appears in many foods, so reading ingredient labels can help you understand exactly what your baby is eating.

If you are introducing soya specifically as an allergen, choose a simple, age-appropriate food so that you can identify the ingredient clearly.

If your baby has a diagnosed allergy or has been prescribed a specialist formula, speak to your healthcare professional before changing their diet.

What does an allergic reaction look like?

Food allergy symptoms can vary.

According to the NHS, possible signs include:

diarrhoea or vomiting
coughing
wheezing or shortness of breath
an itchy throat or tongue
itchy skin or a rash
swelling of the lips or throat
a runny or blocked nose
sore, red or itchy eyes

A baby does not need to have every symptom for an allergic reaction to be possible.

If you think your baby has reacted to a food, stop offering that food and seek medical advice.

What is anaphylaxis?

In a small number of cases, a food can cause a severe allergic reaction called anaphylaxis.

This can be life-threatening and needs immediate emergency treatment.

If your baby develops severe symptoms such as difficulty breathing, significant swelling involving the mouth or throat, or becomes very unwell or unresponsive after eating, call 999 immediately.

Do not wait to see whether severe symptoms settle on their own.

What if your baby gets a little redness around their mouth?

Not every patch of redness after eating is necessarily a food allergy.

Some foods can irritate sensitive skin, particularly around the mouth, and babies may also develop unrelated rashes.

However, it is not always possible for a parent to confidently distinguish irritation from an allergic reaction at home.

If you are unsure whether your baby has reacted to a food, take note of what they ate and what happened, and ask your GP or health visitor for advice before offering the suspected food again.

If symptoms are severe, seek emergency help.

What if your baby has eczema?

If your baby has eczema, particularly if it is significant or persistent, speak to your GP or health visitor about introducing allergenic foods.

The NHS specifically advises parents to take extra care if their baby already has eczema or a diagnosed food allergy.

You may be given individual advice based on your baby’s medical history.

Avoid delaying allergens simply because you are worried without first discussing it with a healthcare professional. The best approach may depend on your baby’s individual circumstances.

What if allergies run in the family?

A family history of food allergy, eczema, asthma or hay fever is another reason to speak to your GP or health visitor before introducing allergenic foods.

This does not automatically mean your baby will develop an allergy.

It does mean professional advice can help you decide how to approach introductions safely and confidently.

Give your healthcare professional as much useful information as possible, including which family members have allergies and what type of reactions they experience.

Should you introduce allergens in the morning?

Parents are sometimes advised informally to introduce allergens earlier in the day so they can observe their baby afterwards.

The NHS’s central guidance is to introduce allergenic foods one at a time and in very small amounts so reactions can be identified.

Rather than becoming anxious about finding a perfect time of day, choose a time when you can pay attention to your baby and are not rushing through the meal.

If a healthcare professional has given you a specific introduction plan because your baby is considered at higher risk, follow that plan.

Should you introduce several allergens in one week?

You do not need to introduce every allergen immediately.

The important point is that potentially allergenic foods are introduced individually at first rather than several new ones at the same time.

Once a food has been tolerated, it can become part of your baby’s normal diet while you gradually introduce other foods.

This can make the process feel much more manageable.

There is no prize for completing a checklist quickly. The aim is to build a varied diet safely and steadily.

What happens after your baby tolerates an allergen?

Once your baby has eaten an allergenic food without a reaction, keep offering it as part of their usual diet.

NHS guidance specifically recommends continuing tolerated allergenic foods rather than introducing them once and then avoiding them for long periods.

You can include them naturally within meals in age-appropriate forms.

For example, tolerated egg might appear at breakfast, yoghurt might be served with fruit, or smooth peanut butter might be mixed into another suitable food.

You do not need to turn every serving into an allergy test.

Should you avoid allergens to prevent food allergies?

For most babies, routinely avoiding allergenic foods is not recommended.

Current NHS advice supports introducing these foods from around 6 months as part of the normal weaning diet.

Evidence has particularly changed thinking around peanuts and eggs. Delaying them does not appear to offer protection and may increase the risk of allergy if introduction is delayed beyond 6 to 12 months.

The exception is when your baby’s healthcare professional has advised avoidance because of a diagnosed or suspected allergy.

Do not deliberately give a food that your baby has already been told to avoid.

Keep introductions calm and simple

You do not need an elaborate system for introducing allergens.

A practical approach is to:

Wait until your baby is ready for solid foods at around 6 months.
Choose one allergenic food.
Prepare it in a safe, age-appropriate form.
Offer a very small amount.
Watch for signs of a reaction.
If tolerated, continue including it in your baby’s diet.
Introduce other allergens individually.

If your baby is at increased risk of allergy, get individual advice before starting.

Having a clear plan can make the process feel less intimidating without turning every meal into something frightening.

When to get professional advice

Talk to your GP or health visitor before introducing allergenic foods if your baby already has eczema, a diagnosed food allergy, or there is a family history of food allergies, eczema, asthma or hay fever.

Seek medical advice if you think your baby has reacted to a food, even if the symptoms were not severe. Keep a note of the food, how much was eaten, when symptoms began and what the symptoms looked like. This information may help your healthcare professional.

Do not remove major food groups from your baby’s diet for long periods without professional guidance, as unnecessary restriction can make it harder to provide a balanced diet.

A severe allergic reaction is an emergency. If your baby develops serious breathing difficulty, significant swelling of the mouth or throat, becomes very unwell or unresponsive, call 999 immediately.