Introducing Allergens to Your Baby: One at a Time, Then Keep Them Going

The NHS advises starting solid food at around 6 months and introducing the foods that most often cause allergies from then on: one at a time, in very small amounts, and then keeping each one in your baby's diet once it is tolerated. Delaying foods like egg and peanut beyond 6 to 12 months may make an allergy more likely, not less.

The hard part is less the advice than the bookkeeping. Over a few weeks you are juggling which allergens your baby has tried, which went fine, and which ones you have not offered for a while.

Is your baby ready?

The NHS lists three signs that usually appear together around 6 months:

1. Your baby can stay in a sitting position and hold their head steady.
2. They can coordinate their eyes, hands, and mouth to pick up food and put it in their mouth.
3. They can swallow food instead of pushing it back out.

Chewing fists, wanting extra milk feeds, or waking at night are not signs of readiness on their own.

If your baby has eczema or an existing food allergy, talk to your GP, health visitor, or pediatrician before you start with allergens.

The foods to introduce

The NHS lists these foods that can cause allergic reactions:

• cow's milk (in cooking or mixed with food)
• eggs
• foods that contain gluten, such as wheat, barley, and rye
• nuts and peanuts (crushed or ground, never whole)
• seeds (crushed or ground)
• soya
• fish
• shellfish (never raw or lightly cooked)

One at a time, in small amounts

Offer each new allergen on its own, so that if there is a reaction you know which food caused it. Start with a very small amount. If it goes well, you can offer more next time.

Reactions usually start within minutes, but can take up to a couple of hours, and some, such as cow's milk allergy, can take longer. That is one reason to offer new allergens earlier in the day, when you can watch your baby for a while afterwards.

Keep them going

Once your baby has eaten an allergen without a problem, the NHS advises keeping it as part of their usual diet. A food that was tolerated once and then dropped for months is easy to lose track of, so a simple record of the last time each allergen was offered helps.

When to get help

Mild symptoms, such as a few hives around the mouth, are a reason to stop that food and speak to your GP or health visitor.

Call 999 (or your local emergency number) straight away if your baby has swelling of the lips, mouth, or tongue, struggles to breathe or breathes very fast, turns pale or blue, becomes floppy or unresponsive, or suddenly seems very drowsy. These can be signs of anaphylaxis.

Tracking allergens in BabyTrack+

The solids tracker in BabyTrack+ follows nine common allergens: milk, egg, peanut, tree nuts, wheat, soy, fish, shellfish, and sesame. It splits peanut from tree nuts and uses wheat and sesame for the NHS groups "gluten" and "seeds".

When you log a meal, you pick the foods from a list of 110 first foods (or type your own) and how much your baby ate: tasted, some, most, or all. The app then:

• marks each allergen as “Not started”, “Introduced”, or “Keeping up”
• warns you if one meal contains two new allergens
• flags an introduced allergen you have not offered for about a week
• records any reaction against the food that caused it, and shows an emergency notice for swelling or breathing problems

Solids are counted separately from milk feeds, so your feed totals stay accurate. The app turns the solids tracker on at 6 months, or earlier if you log a solids meal.

BabyTrack+ is a log, not medical advice. Your pediatrician or health visitor knows your baby and should be your first stop for questions about allergies.