Allergy-proof your weaning plan: when to introduce nuts, eggs and milk, and what to watch for

“Food allergies can develop from a very young age,” says Annette Weaver, a registered dietitian and clinical dietetic advisor at Allergy UK. “It’s important to remember that most children do not develop food allergy and tolerate a wide variety of foods without any issues. Excessive anxiety around food can be unhelpful for parents and children.”

“In general, there’s no need to worry about food allergies unless there are specific symptoms suggesting a problem,” she says.

We asked Annette some of the most common questions about allergies and weaning, to help you feel informed and confident when starting your baby’s food journey.

What are food allergies and why do they happen in the first place?

Our immune systems are there to protect us against anything harmful that enters our bodies — but sometimes they overreact to harmless substances, like dust, pollen, or foods, causing an allergic reaction.

We don’t fully understand why some peoples’ immune systems see foods as harmful, but Annette says that several things could play a role, including “genetics, environment, reduced exposure to a diversity of microorganisms, immune system imbalances, and impaired skin barrier issues.”

“Conditions like eczema can allow allergens to enter through the skin instead of the gut,” she says. “The immune system may misinterpret them as threats, triggering allergic sensitisation instead of tolerance.

“The more severe the eczema is and the earlier it started, the higher the risk is of food allergy.”

What makes children more likely to develop a food allergy?

Allergies are common — Allergy UK estimates that more than one in four people in the UK are affected by an allergy at some point in their lives, and they’re particularly common in kids.

But there are several risk factors that make food allergies more likely:

• A family history of allergies (although they may not have the same allergies as their parents)
• Growing up in urban or industrialised areas, where “there is lower exposure to natural environments and microbial diversity which may increase the risk of allergies,” Annette says.
• Eating a diet that is high in ultra-processed foods and sugars — but the research on this is still emerging, Annette says.
• Delaying the introduction of peanuts or eggs in high-risk babies
• Having eczema, asthma, or hay fever — “Eczema, hay fever, asthma and food allergies are all related allergic conditions that often share genetic and immune system traits. People with eczema or hay fever tend to have an overactive immune response, which increases their risk of reacting to harmless substances like foods,” Annette says.

When should you start looking for allergies in your child?

“Food allergy symptoms in exclusively breastfed babies are rare but possible, as small amounts of food proteins can pass through breastmilk. Formula-fed babies may react to formula milk from early infancy,” Annette says.

When it comes to introducing solid foods, Annette recommends introducing foods that are more commonly linked with allergies one at a time and watching for possible reactions.

Which foods are most likely to trigger a reaction?

“It is possible to be allergic to any food,” Annette says. But the most common food allergens in children in the UK are:

• Cow’s milk
• Hen’s eggs
• Peanuts
• Tree nuts
• Wheat
• Soya
• Fish
• Shellfish

How to introduce foods that are common allergens

Annette shares her tips on how to best introduce common allergens:

• Introduce a new allergenic food one at a time, on separate days when your child is well.
• Give your child new foods early in the day to allow time to monitor them afterwards.
• Stay with your child when feeding them and stop giving them the food if you suspect they are having a reaction to it.
• With any new allergenic food, start slow (e.g. with ¼ of a teaspoon) and gradually increase over the next few days if the food is tolerated.
• Once the food is successfully introduced, it is important to continue to give them the food regularly as part of their normal diet.
• Don’t force foods. If the child doesn’t eat the food, try on a different day.

If you as the parent are allergic to a food, Annette says you “should seek individualised advice from healthcare professionals who can consider the risk to the baby and parents.”

“A clear plan needs to be developed for how introduction and regular intake thereafter will be achieved, for example, by a different caregiver who regularly looks after the baby,” Annette says.

Introduce eggs and peanuts to babies who have a higher risk of food allergies early

“For guidance on identifying high-risk infants and safely introducing allergens, see the BSACI parent guide,” Annette says.

If your child is at a higher risk of having a food allergy, introducing them to eggs and peanuts earlier on in the weaning journey can reduce their risk of developing an allergy to them (if they don’t have the allergy already).

They can start eating eggs and peanuts when they can comfortably swallow pureed vegetables – any time after 6 months. Peanuts should not be given whole until at least 5 years of age and should be given in age-appropriate form like peanut butter. According to the British Society for Allergy & Clinical Immunology, the risk of anaphylaxis or a severe reaction is low — one or two per 1000.

How to prepare common allergens for your child

For foods that are common allergens in children, Annette gave the following recommendations for preparing and serving them in the weaning stage:

Eggs: Choose fresh, in date, British Lion-stamped eggs, as these have been laid by chickens vaccinated against salmonella to reduce risk of food poisoning.

For the first time you give your baby egg, give them ¼ tsp egg (both white and yolk) mashed into other food that you know they can eat with no problems — e.g. fruit, vegetables, yoghurt, or baby rice.

If that goes down ok, offer your baby scrambled or boiled eggs, or omelettes, and continue to use both the white and the yolk.

Peanuts and tree nuts: Use smooth nut butters or grind whole nuts to a fine powder. Mix this with fruits, vegetables, yoghurt or baby cereals, or add to your baby’s milk.

IMPORTANT: Never give whole nuts, coarsely chopped nuts or chunks of nut/peanut butter to children under five years of age as these are a choking risk.

Wheat: Try Weetabix or similar breakfast cereals, well cooked pasta shapes, toast fingers, or couscous.

Fish and seafood: Puréed, flaked or mashed cooked fish — such as cod, haddock, salmon or trout — or seafood — such as prawns or crab — are good to give a weaning baby.

Seeds: Hummus, which contains tahini (sesame paste), or crushed seeds added to foods like yoghurt or puréed fruit can be a good way to introduce seeds.

Cow’s milk: Add fresh whole milk to foods like mashed potato or sauces. Or give your baby yoghurt or fromage frais with no added sugar.

What does an allergic reaction look like in a baby?

“Children under one year of age often experience milder allergic symptoms compared to older children and adults, and the risk of severe allergic reactions (anaphylaxis) is generally lower but not absent,” Annette says.

An allergic reaction in a baby might involve the following symptoms:

• Hives
• Skin rash
• Vomiting
• Breathing issues like coughing or wheezing
• Swelling of the lips, tongue, throat, or face

It’s important to note that not all skin rashes from food are due to an allergy. Some foods, like citrus fruits, tomatoes, and strawberries, can irritate the skin, especially around the mouth. You can avoid this by using a barrier cream on your baby’s skin.

Some of these symptoms are easy to see, but other symptoms can be hard to detect because babies can’t tell you about them — like an itchy mouth or pain in the throat or stomach. So, it’s important to watch your baby closely for any sign of a reaction.

“Babies’ signs of distress can sometimes be subtle or non-specific,” Annette says, “like crying, irritability, or other general signs of distress.”

If a baby is experiencing anaphylaxis, which is a severe and life-threatening allergic reaction, their symptoms will affect their breathing and consciousness. Signs of anaphylaxis include:

• Persistent cough
• Wheezing
• Hoarse voice
• Difficulty swallowing
• Swollen tongue
• Difficult or noisy breathing
• Persistent dizziness
• Pale or floppy
• Suddenly sleepy
• Collapsing/unconscious

What should you do if your baby has an allergic reaction?

Firstly, stop feeding your child the food you think is causing a reaction, and stay calm.

If your child’s symptoms are mild, “seek medical advice from a GP, NHS 111, or an urgent care centre,” Annete says. “And give them an antihistamine if advised or already available.”

Then, monitor your child closely to see if symptoms worsen.

If their symptoms are severe, “parents should immediately call 999 (or 112) and use an adrenaline auto-injector (such as an EpiPen or Jext) if prescribed,” Annette says.

“The child should be kept lying down flat with their legs raised and encouraged to stay as still as possible. This position helps keep blood flowing to the heart and brain until emergency help arrives,” she says. “If breathing is difficult, they can sit up slightly, but they should not stand or walk around.”

What should you do after the allergic reaction goes away?

“If a food allergy is suspected, avoid the food and speak to a healthcare professional,” Annette says. “How long the food will need to be avoided depends on the type of allergy and the child’s risk factors.”

“An allergy diagnosis isn’t just a label, it’s the key to managing symptoms, preventing complications and improving quality of life. The earlier you recognise the signs and seek diagnosis, the better you can manage symptoms and take control of the condition,” she says.

Allergy UK’s ‘I Wish I Knew’ campaign highlights the importance of getting allergies diagnosed as soon as possible, especially because treating allergies in infancy can help to increase the likelihood that a child will outgrow the allergy or avoid it getting any worse.

Should you reintroduce foods that your child has a reaction to?

“Children can grow out of certain food allergies, particularly to cow’s milk and egg,” Annette says.

“In many cases, carefully introducing small amounts of well-baked forms of these foods and gradually increasing amounts to tolerance and progressing to less well-baked forms may help with this process.”

There are ‘food reintroduction ladders’ which give parents a process to follow when reintroducing foods — but you should always check whether this is safe and only do it with guidance from a qualified health professional.

Immunotherapy, or desensitisation, may be an option for your child if they have certain allergies. This is a treatment where people are exposed to increasing amounts of allergens over time, with the aim of reducing their reactions to the allergen. It’s currently only available privately, but Annette says it “should only be done under the care of a specialist allergy clinic.”