Introducing allergenic foods is one of the parts of weaning that worries parents most. If you are wondering how to introduce allergenic foods to your baby safely, the key points are simple: introduce them early, one at a time, in a suitable form, and keep offering them regularly. This article explains the general approach in plain language, but it is not medical advice for your own baby, so talk to your GP or health visitor if your baby has eczema, a known allergy, or a family history of food allergy.
For more weaning guidance, including first foods and signs of readiness, see the other articles on Healthy Baby Guide.
What are allergenic foods?
Allergenic foods are foods that commonly cause allergic reactions. The main ones to think about during weaning are peanut, egg, cow’s milk, wheat, soya, fish, shellfish, sesame, and tree nuts such as cashew and hazelnut. These foods are also nutritious and, for most babies, they can be part of a varied diet from the start of weaning.
For many years, parents were told to delay these foods. Current guidance in the UK has moved away from that. Delaying allergenic foods does not prevent allergy, and for many babies, regular early exposure is part of building tolerance. That said, every baby is different, and babies with severe eczema or an existing food allergy need individual advice before these foods are introduced at home.
When should allergenic foods be introduced?
Most babies are ready to start solids at around six months, when they can sit up with support, hold their head steady, and show interest in food. Allergenic foods can be introduced from the start of weaning, once your baby is eating other foods well. There is no need to wait until your baby is older, and no need to introduce every allergen in the first week.
A calm, practical approach is to introduce one new allergenic food at a time, so that if your baby reacts, you know which food was involved. Wait a few days before introducing the next new allergen, while continuing to offer the first one. Keep portions tiny at first, just a taste or a small spoonful mixed into a familiar food.
How to introduce each food safely
Preparation matters, because the form of the food must suit a baby who is learning to eat. Never give whole nuts, chunks of nut butter, or hard pieces that could cause choking. Use smooth, soft, well-mixed forms, and always stay with your baby while they eat.
Peanut and tree nuts
Use smooth peanut butter thinned with a little water, breast milk, or formula, and stir it into porridge or a soft puree. A thin smear on a strip of soft toast is also suitable once your baby can manage finger foods. Do not use crunchy peanut butter or whole nuts. Start with a small amount, such as a quarter of a teaspoon of smooth peanut butter, and build up gradually over several days.
Egg
Offer well-cooked egg, such as hard-boiled egg mashed with a little milk, or scrambled egg cooked until firm. Both the white and the yolk can be offered. Start with a small piece or a spoonful, and watch how your baby responds. Raw or lightly cooked egg is not suitable for babies.
Cow’s milk, wheat, fish and other allergens
Cow’s milk can be used in cooking and mixed into foods from the start of weaning, although it should not replace breast milk or formula as the main drink until after twelve months. Wheat can be offered as porridge, pasta, or soft bread. Fish should be well cooked, soft, and carefully checked for bones. Soya can be offered as tofu or in cooked dishes. Sesame can be offered as a thin smear of tahini mixed into food. Keep each new food separate at first so you can spot any reaction.
Signs of a reaction to watch for
Most reactions are mild and appear within minutes to a couple of hours of eating. Watch for:
- Hives, a rash, or red, itchy patches of skin.
- Swelling of the lips, face, or tongue.
- Vomiting, diarrhoea, or tummy pain soon after eating.
- Sneezing, a runny nose, coughing, or wheezing.
- Unusual sleepiness, floppiness, or distress.
If your baby has mild symptoms, stop offering the food and contact your GP or health visitor for advice. If your baby has trouble breathing, widespread swelling, or becomes very unwell, treat it as an emergency and call 999. Do not try a food again at home after a worrying reaction until you have professional advice.
When to get advice before you start
Talk to your GP, health visitor, or an allergy specialist before introducing allergenic foods at home if your baby has moderate or severe eczema, has already had a reaction to a food, or has a close family history of allergy. In some cases, a professional may advise allergy testing or a supervised introduction. That advice protects your baby and gives you confidence.
For babies without those risk factors, home introduction following the steps above is the usual approach. If you are unsure which group your baby is in, ask. A short conversation with your health visitor is worth more than weeks of worry.
