Introducing Allergens to Your Baby: What to Know
Updated September 2025 · 6 min read
Current guidance is to introduce common allergen foods — such as peanut, egg, dairy, wheat, soy, fish, shellfish, tree nuts and sesame — deliberately from around six months, when you start solids, rather than delaying them. Offer one new allergen at a time, in a baby-safe form, and watch for reactions. If your baby has severe eczema or a known food allergy, talk to your doctor before introducing peanut or egg.
- Introduce common allergens from around 6 months — delaying doesn’t help and may raise risk.
- Offer one new allergen at a time, then wait a few days before the next.
- Use baby-safe forms (e.g. smooth peanut butter thinned, never whole nuts).
- If your baby has severe eczema or a known allergy, speak to your doctor first.
Early introduction is now advised
Advice on allergens has changed. Rather than holding common allergen foods back, current guidance is to introduce them from around six months, as part of starting solids. Research suggests that introducing foods like peanut and egg early — not late — can actually help reduce the chance of developing a food allergy.
The common allergens
Most food allergies involve a short list of foods: peanut, tree nuts, egg, cow’s milk (dairy), soy, wheat, fish, shellfish and sesame. These can all be introduced in baby-safe forms.
How to introduce them safely
- One at a time. Introduce a single new allergen, then wait a few days before the next, so you can link any reaction to a specific food.
- Baby-safe forms. Never give whole nuts or big spoonfuls of thick nut butter (choking risk) — instead use smooth peanut butter thinned with a little water or mixed into purée, well-cooked egg, plain yoghurt, or finely ground nuts.
- Earlier in the day is often suggested, so you can watch your baby over the following hours.
- Keep it in the diet. Once a food is tolerated, keep offering it regularly — occasional exposure isn’t as protective.
When to talk to your doctor first
If your baby has severe eczema, an existing food allergy, or a strong family history, speak to your paediatrician or an allergist before introducing peanut or egg — they may recommend testing or introducing under guidance. This is important, so don’t skip it if it applies to your baby.
Signs of an allergic reaction
Mild reactions can include a few hives, redness around the mouth, or mild swelling. Stop the food and speak to your doctor. Seek emergency help immediately if you see signs of a severe reaction (anaphylaxis): swelling of the lips, tongue or throat, difficulty breathing, wheezing, widespread hives, vomiting, floppiness or a sudden change in colour. If in doubt, call emergency services.
Frequently asked questions
When should I introduce allergens to my baby?
From around six months, when you start solids u2014 current guidance advises introducing common allergens early rather than delaying them, which can help reduce allergy risk. Introduce one at a time.
How do I give my baby peanut safely?
Never whole nuts or thick spoonfuls of nut butter, which are choking hazards. Use smooth peanut butter thinned with a little water or mixed into puru00e9e, or finely ground nuts.
What are the signs of a food allergy in babies?
Mild signs include hives, redness or mild swelling around the mouth. Severe signs u2014 swelling of the lips or throat, difficulty breathing, widespread hives, vomiting or floppiness u2014 are a medical emergency; call for help immediately.
Sources
Feeding and safety guidance in this article reflects the recommendations of bodies such as the American Academy of Pediatrics (AAP), the World Health Organization (WHO) and the UK’s NHS. It is general information, not medical or dietary advice — always follow the guidance of your own paediatrician, health visitor or a registered dietitian, especially if your baby has allergies, reflux or any health condition.