Baby Allergen Introduction Guide: When and How

Before you start: timing and individual advice

For most babies, introducing allergenic foods is part of starting solids around six months. The NHS recommends small amounts, one new allergenic food at a time. ASCIA 2026 prioritises well-cooked egg and appropriately thinned peanut soon after solids begin, with continued inclusion if tolerated. The CDC also connects starting solids to developmental readiness, rather than a date alone.

Ask your GP, health visitor or allergy team for individualized guidance if your baby has severe eczema, an existing egg allergy, a previous food reaction or another diagnosed allergy. NIAID has a special peanut-introduction pathway for severe eczema and/or egg allergy, sometimes before six months after appropriate clinical assessment. This is not a blanket instruction to introduce foods before readiness.

This article uses UK guidance for the practical examples and identifies US sources separately. If your local clinician has given different instructions, clarify the reason with them. We do not prescribe a universal dose, a testing programme or a fixed schedule for higher-risk babies.

Choose the allergen and its food form separately

A food can be suitable for introduction while a particular shape or product remains unsuitable. Whole nuts and thick spoonfuls of nut butter are choking hazards; raw shellfish and unpasteurised cheeses raise different food-safety concerns. Check the NHS foods-to-avoid guidance as well as the ingredient label.

The FDA’s nine major US allergens are milk, egg, fish, crustacean shellfish, tree nuts, peanuts, wheat, soy and sesame. This is a labelling category, not a complete list of foods that can cause reactions. UK guidance also discusses foods such as celery and mustard. Do not interpret an unlisted food as guaranteed allergy-free.

Peanut and tree nuts

Consider smooth nut butter mixed into a familiar food, rather than whole nuts or a thick spoonful. Check which nut the product actually contains.

Egg

A small amount of thoroughly cooked egg avoids the regional exceptions around raw or lightly cooked eggs. Use a texture your baby already manages.

Milk

Plain yoghurt or an appropriate pasteurised cheese is different from replacing breast milk or formula with cows’ milk as a drink.

Wheat

Check ingredients in foods such as cereal or pasta. A mixed recipe may introduce egg or milk at the same time.

Fish and shellfish

Cook thoroughly, remove bones or shell, and check the preparation carefully. Fish and crustacean shellfish are separate US allergen categories.

Soy and sesame

Read the actual product label. Soy products and sesame-containing mixtures can include additional allergens.

These are ingredient-selection examples, not photographed serving instructions. For preparation, use the NHS food-preparation guidance and the relevant food profile. Age labels do not establish that a particular texture is right for an individual child.

Make the first offer easy to understand

Choose a simple food combination with a clear ingredient list. For example, if a familiar porridge is being used to carry a new ingredient, check that the porridge itself does not introduce another new allergen. A recipe labelled “peanut” may also contain milk, wheat or sesame.

1. Read the label before cooking. Check the complete ingredients, the allergen information and any changes since you last bought the product.
2. Keep the new ingredient identifiable. Offer only one new allergenic food at a time, in the small amount recommended by your applicable guidance or clinician.
3. Prepare the food for the child. Consider texture, shape and temperature, and stay with your baby while they eat.
4. Leave space to notice what happens. Do not rely on a timer or the absence of a skin rash as proof that every possible reaction has been excluded.

The purpose is to make the event understandable, not to complete every allergen as quickly as possible. This guide does not turn a successful first taste into a guarantee about future meals.

Keep a record that will actually help

A useful record describes the food and what you observed. “Peanut: done” leaves out information that could matter when discussing a concern. You can use paper, a phone note or a food tracker; the format matters less than the detail.

• The date and approximate time.
• The exact food, product or recipe, including its other ingredients.
• The preparation and approximate amount actually eaten, rather than only the amount offered.
• Any symptoms, when they appeared and how long they lasted.
• The advice received and any next steps agreed with a healthcare professional.

Keep the packaging or a photograph of the ingredient label if there is a concern. Record observations in plain language rather than assigning your own diagnosis. A log supports a conversation with a professional; it cannot diagnose an allergy or make a home reintroduction appropriate.

Recognise a possible reaction and seek appropriate help

Possible reactions include an itchy rash, swelling of the lips or face, vomiting, coughing or wheezing. This is not a complete checklist, and these symptoms can have other causes. The NHS describes both reactions that occur soon after eating and delayed symptoms. Timing and appearance alone cannot reliably identify the cause at home.

If you suspect a reaction, stop offering the suspected food and get medical advice about what happened and what to do next. For symptom assessment and medical diagnosis boundaries, see food allergy symptoms in babies. Do not use a second home taste to test your theory. Follow a prescribed allergy plan if your child has one.

For suspected anaphylaxis, use the emergency instructions above immediately. Do not wait for a rash or try to judge severity from a photograph or app.

Avoid removing whole food groups for an extended period without professional advice. If milk or another important food needs to be excluded, ask how your baby’s nutritional needs will be met.

After a food is tolerated, think beyond the first taste

NHS guidance recommends keeping tolerated allergenic foods in the usual diet. Our ongoing-exposure guide explains practical inclusion without treating an arbitrary dose as an allergy guarantee. ASCIA 2026 recommends offering tolerated common allergens at least weekly, a practical expert-consensus recommendation rather than a guaranteed allergy-prevention dose. Follow any individualized instructions about continued exposure.

Make this practical by noting a few existing meals that use the ingredient and checking their other allergens. You might keep a short list of breakfast, lunch and snack options rather than inventing an entirely new meal for every exposure. Recheck labels when the product or recipe changes.

Questions that come up in real meal planning

Do I need to wait exactly three days between allergens?

The US CDC recommends waiting three to five days between new single-ingredient foods when first starting solids; this is general food-introduction guidance. The UK NHS recommends introducing potentially allergenic foods one at a time, without specifying that same universal interval on its page. These are different recommendations. Follow the guidance that applies to your baby and ask your clinician if you are unsure. An individual allergy plan takes priority over a generic app calendar.

Can I use a recipe containing several allergens?

Check each ingredient against what your baby has already tried. A mixed recipe is harder to interpret if several ingredients are new. Keep the full recipe in your notes, including optional additions and substitutions, so “egg pancake” does not hide the milk or wheat it also contains.

Is a food marked “tried” now allergy-free for my baby?

No. “Tried” records an event. It does not certify future tolerance, diagnose a reaction or mean that every product containing the ingredient has the same formulation. Keep following applicable guidance and seek advice if new symptoms appear.