The first spoonful of peanut butter or egg can feel surprisingly nerve-racking, even for parents who are relaxed about everything else. Knowing exactly what to offer, how much and what to watch for turns introducing allergens to your baby into a calm, ordinary part of weaning.
Quick answer: Start introducing common allergens such as egg, peanut, dairy, wheat, sesame and fish from around 6 months, once your baby has started solids. Offer one new allergen at a time, in a small amount mixed into a familiar food, at home and earlier in the day, then watch for about 2 hours. Once a food is tolerated, keep offering it regularly. If your baby has severe eczema or a known food allergy, speak to your paediatrician first.
Key takeaways
- The main food allergens to introduce are cow's milk, egg, peanut, tree nuts, sesame, wheat (gluten), soy, fish and shellfish.
- Guidance from the NHS and the American Academy of Pediatrics is not to delay allergens; introducing them during the first year, from around 6 months, may lower the chance of some allergies, such as peanut and egg.
- Introduce one new allergen at a time and leave about 2 to 3 days before the next new one, so you can tell what caused any reaction.
- Start with about a quarter of a teaspoon and build up over a few days to 1 to 2 teaspoons.
- Most immediate allergic reactions appear within minutes and up to about 2 hours after eating.
- Once tolerated, keep each allergen in your baby's diet regularly, ideally around twice a week, to help maintain tolerance.
Which foods are the common allergens?
A small group of foods causes most food allergies in babies and young children. Here is how to offer each one safely for the first time.
| Allergen | Safe first ways to offer | Avoid |
|---|---|---|
| Egg | Well-cooked egg: hard-boiled and mashed into purée, or soft omelette strips | Raw or runny egg |
| Peanut | Smooth peanut butter thinned with breast milk, formula or water, or stirred into purée | Whole or chopped peanuts, thick dollops of peanut butter |
| Tree nuts | Smooth almond or cashew butter, or finely ground nuts mixed into food | Whole or chopped nuts |
| Sesame | Tahini stirred into purée, or a little homemade hummus without added salt | Salty shop-bought dips |
| Cow's milk | Full-fat plain yoghurt, pasteurised cheese, milk used in cooking | Cow's milk as a main drink before 12 months |
| Wheat (gluten) | Wheat-based cereal, soft pasta, toast fingers | Very salty breads and crackers |
| Soy | Soft tofu, plain soy yoghurt | Salty soy sauce |
| Fish | Well-cooked, boneless salmon or white fish, flaked or blended | Bones; shark, swordfish and marlin |
| Shellfish | Well-cooked prawns, finely chopped or blended | Raw or undercooked shellfish |
How do you introduce allergens to your baby, step by step?
- Start solids first. Begin with a few first foods such as vegetables and fruit. Allergens can be added soon after, from around 6 months.
- Pick the right moment. Choose a day when your baby is well, at home, earlier in the day and not just before a long nap, so you can watch them for 2 hours afterwards.
- Offer a tiny amount. Mix about a quarter of a teaspoon of the allergen into a food your baby already eats happily, such as sweet potato purée.
- Watch and wait. If there are no signs of a reaction, offer the rest of the portion. Keep watching for about 2 hours.
- Build up gradually. Over the next few days, offer the same food again, increasing to around 1 to 2 teaspoons.
- Move on to the next allergen. Leave 2 to 3 days before introducing another new allergen.
- Keep it going. Once a food is tolerated, offer it regularly as part of your baby's normal meals.
A simple order many families follow is egg, then peanut, then dairy and wheat, followed by sesame, tree nuts, fish, soy and shellfish over the next few weeks. There is no single correct order, so fit it around what you already cook at home.
What does an allergic reaction look like?
Mild to moderate reactions
- Raised, itchy red rash (hives) on the face or body
- Swelling of the lips, face or around the eyes
- Sudden vomiting or tummy pain
Stop offering the food and contact your paediatrician. Redness only where food touched the skin, especially after tomato or citrus, is often simple irritation, but mention it if you are unsure.
Severe reactions (anaphylaxis)
- Difficulty breathing, noisy breathing or wheezing
- Persistent coughing, a hoarse cry or difficulty swallowing
- Swelling of the tongue
- Becoming pale, floppy or unresponsive
If you notice any of these, call an ambulance on 998 immediately.
Some reactions, especially to cow's milk, are delayed and appear hours or days later as worsening eczema, diarrhoea, reflux or blood in the nappy. Keep a short food diary and talk to your paediatrician if a pattern appears.
What if my baby has eczema or a family history of allergy?
Babies with severe or early-onset eczema, or an existing food allergy, have a higher chance of developing peanut and egg allergy. Speak to your paediatrician before introducing these foods. They may recommend introducing them earlier, sometimes with allergy testing first, rather than waiting.
A family history of allergy on its own is not usually a reason to delay. If your baby's skin is often flared, our guide to managing baby eczema day to day may help, alongside medical advice.
How can you make introducing allergens to your baby easier?
- Use familiar carriers. Stir peanut butter or tahini into a purée your baby already loves, so the only new thing is the allergen.
- Prepare small portions. A Turtees 4-in-1 Baby Food Maker steams, blends, chops and defrosts in one bowl, which makes it easy to steam a little salmon, then blend it with vegetables. It has dishwasher-safe components and is priced at AED 220.
- Clean between allergens. Wash the bowl, blade and spoons thoroughly so traces of one food do not muddy the picture when you introduce the next.
- Keep a simple diary. Note the date, food, amount and any reaction. It is very helpful if you ever need to see a doctor.
- Brief your carers. Introduce new allergens at home yourself, and tell your nanny or nursery which foods your baby already tolerates.
For textures and first-food ideas, see our comparison of baby-led weaning vs purées and our guide to batch-cooking baby food.
Frequently Asked Questions
At what age should I introduce peanut to my baby?
For most babies, from around 6 months, once they have started solids and are eating a few first foods. Offer smooth peanut butter thinned into a purée, never whole or chopped peanuts. If your baby has severe eczema or an existing food allergy, speak to your paediatrician first, as they may advise earlier introduction or testing.
How long should I wait between new allergens?
Leave about 2 to 3 days between each new allergen. This makes it easier to work out which food caused any reaction. Non-allergenic foods, such as new vegetables and fruit, can be introduced in between. Once a food has been offered a few times without problems, it can be combined freely with others.
Can I introduce allergens if my baby is unwell?
It is best to wait until your baby is well again. A cold, fever, tummy bug or eczema flare can make it harder to tell whether a symptom is caused by a new food or by the illness. Pick a calm day when your baby is healthy and you can watch them closely for a couple of hours.
What should I do if my baby reacts to a food?
Stop giving the food. For mild symptoms such as a few hives, contact your paediatrician, who may suggest medication and arrange an allergy assessment. For breathing difficulty, tongue swelling, persistent coughing, or a pale, floppy baby, call 998 immediately. Do not reintroduce the food until a doctor has advised you.
Does breastfeeding prevent food allergies?
Breastfeeding has many benefits for babies and mothers, but current evidence does not show that it reliably prevents food allergies on its own. Carry on breastfeeding while you introduce solids and allergens. There is generally no need to avoid allergenic foods in your own diet unless a doctor has advised it for your baby.
This article is for general information and isn't a substitute for advice from your doctor or paediatrician.
Introducing allergens to your baby does not need to be dramatic. A small spoon, a familiar purée and a quiet morning at home are usually all it takes. Go one food at a time, keep favourites in the rotation, and lean on your paediatrician whenever you have questions.
