The information within this post is for general advice only. If your child is experiencing symptoms of an allergic reaction, speak to your health care professional.

The first spoonfuls of solid food are a big step for parents. Between choosing the right textures, watching for reactions, and keeping note of all the different foods, there are plenty of things to consider.

A common area of uncertainty for parents is how to navigate the introduction of food allergens. Research shows that introducing common allergens like egg, peanut, soy, wheat, and fish early and often can help reduce the likelihood of developing food allergies later in life.¹ Every baby’s journey is unique and with the right approach, introducing allergens can be a smooth and confident process. In this blog we take you through common allergens to introduce to your baby, including what age they can begin starting, and how to do it. Let’s take a look.

What age should a baby be introduced to allergens?

So when should you introduce allergens to your baby? It's generally recommended that common food allergens should be introduced around 6 months of age. You shouldn’t introduce solids, including allergens, before 4 months of age.¹ This timing supports your baby’s natural development and may help reduce the risk of food allergies later on.

However, before you start solids, look for the signs that your baby is ready. These may include:²

• Being able to sit with good head and neck control
• Showing interest in food when others are eating
• The ability to open their mouth for a spoon and move food to the back of their mouth to swallow.

If your baby isn’t quite showing these signs yet, there’s no need to rush. Waiting until they’re developmentally ready helps ensure that their digestive system and immune system are prepared for new foods.

How to introduce allergens to baby safely

Most babies tolerate allergens well. The goal is to introduce them gradually and confidently once your baby is ready, then keep them in their diet regularly.³ Here’s a quick step-by-step guide on how to introduce allergens safely.

1. Offer one new allergen at a time. This helps you identify what food has caused a reaction, if they have one.
2. Start with a very small amount. You can try a fraction of a teaspoon or mix a small amount into a familiar food.
3. Observe your baby for any signs of reaction (such as rash, vomiting, or sudden fussiness).
4. If tolerated, continue offering that food a few times each week to help maintain tolerance.
5. It can be a good idea to introduce a food allergy diary, keeping note of specific foods and how your baby reacts to them.

For more guidance on introducing allergens to your baby, speak to your healthcare professional or visit https://preventallergies.org.au/

Introducing egg to a baby

Egg is one of the most common food allergens.¹ When introducing it try starting with a small amount of well-cooked egg. You can mash hard-boiled egg or add scrambled egg mixed in with vegetables. Once tolerated, you can gradually increase the portion over several meals.⁴ Avoid raw or lightly cooked egg (e.g., runny yolk) until your child is older.

Possible signs of an egg allergy reaction in a baby can include mild redness or hives around the mouth, vomiting, or irritability.⁵ These usually appear within minutes to two hours. Most are mild, but if you notice breathing difficulty, swelling, or your baby seems suddenly unwell, seek medical help immediately.

Introducing peanut to baby

Peanut is another common allergen, and research shows that early, regular introduction can reduce the risk of developing a peanut allergy.

Offer a small amount of smooth peanut butter thinned with warm water, breastmilk, or formula, or mix it into a puree. Avoid whole peanuts or chunky nut butters, as these can be choking hazards.

If your baby tolerates peanut, keep including it 2–3 times per week as part of their normal diet. As with other allergens, a peanut allergy in a baby can look like skin redness, mild swelling, or vomiting.⁷

Introducing soy to baby

Soy is a relatively uncommon allergy.⁸ Soy can be offered once your baby is confidently eating other solids. Soy containing foods that your baby can try include:

• Soft tofu blended into vegetable purees
• Soy-based infant cereals
• Soy milk used in cooking (not as a primary drink before 12 months).

While uncommon, soy allergy for babies can cause mild or delayed symptoms, such as temporary rash or loose stools.

How to introduce shellfish to baby

Shellfish (such as prawns, crab, or lobster) is one of the top eight food allergens. It’s usually introduced after other allergenic foods have been tolerated. Always make sure the shellfish is fresh, fully cooked, and finely minced to reduce choking risk.⁹

Because reactions can occur even with small quantities, introduce it at home rather than in a restaurant, and keep your baby under observation for a few hours. Signs of a shellfish allergy in a baby can include redness, hives, vomiting, or sudden fussiness.⁹

Introducing wheat to baby

Wheat is a key part of many infant diets and can be introduced once your baby is tolerating other foods well. Start with soft, easy-to-digest wheat-based foods such as:

• Iron-fortified baby cereals
• Small pieces of soft toast or pasta
• Porridge made from wheat

Possible wheat allergy baby symptoms can include mild skin irritation, rash, or digestive upset (vomiting, loose stools). Even following a reaction, most babies outgrow wheat sensitivity as they get older.¹⁰

How many times to introduce allergens to baby

When introducing allergens to baby the key is to be consistent. Once your baby has safely tried an allergenic food, keeping it in their regular diet is key. Research now shows that consistent exposure (around two to three times per week) helps maintain tolerance and supports the immune system’s 'memory' of that food. Regular inclusion of allergenic foods (such as egg, peanut, or soy) reinforces what the immune system has already learned: that these foods are safe. If allergenic foods are introduced but then avoided for long periods, the body may “forget” this tolerance, which could increase the chance of reactions later on.¹¹

If your baby shows any signs of a reaction after eating a new food, the most important thing is to stay calm and act promptly.

1. Stop feeding immediately and observe your baby closely.
2. Mild symptoms (such as a small rash or mild vomiting) should prompt you to contact your GP or child health nurse for advice before offering that food again.
3. If you notice severe symptoms, including swelling of the face, lips or tongue, persistent vomiting, sudden drowsiness, or any difficulty breathing, call 000 for emergency assistance.
4. Keep a simple record of what was eaten and when the symptoms appeared. This information can help your healthcare provider identify the likely trigger and guide next steps.

Before starting allergenic foods, it’s always a good idea to speak with your healthcare professional, especially if they have moderate-to-severe baby eczema, a known food allergy, or a family history of allergic conditions. Your doctor or dietitian can help tailor an introduction plan that’s right for your baby’s needs.

Introducing allergenic foods is a positive and fun step for most families. With the right guidance, it’s an opportunity to help your baby build lifelong tolerance and confidence with new flavours and textures.

Ready to explore more? Head over to the Biostime Parent Lounge for more articles and useful tips.

References:

1. Australasian Society of Clinical Immunology and Allergy. (2024, June). How to introduce solid foods to babies for allergy prevention. Retrieved from https://www.allergy.org.au/patients/allergy-prevention/ascia-how-to-introduce-solid-foods-to-babies
2. The Royal Children’s Hospital Melbourne. (2015, May). Guide to foods: Baby’s first year [PDF]. https://www.rch.org.au/uploadedFiles/Main/Content/nutrition/guide-to-foods-babys-first-year.pdf
3. Allergy & Anaphylaxis Australia. (n.d.). Babies and food allergies. https://allergyfacts.org.au/living-with-allergies/different-lifestages/infant-feeding/
4. The Royal Children’s Hospital Melbourne. (2021, August 23). Home introduction of a new food: Handout. https://www.rch.org.au/uploadedFiles/Main/Content/allergy/RCH%20003%20Home%20Intro%20of%20New%20Food%20handout%20EDITABLE%20GO%20LIVE%20.pdf
5. Healthdirect Australia. (2024). Egg allergy. https://www.healthdirect.gov.au/egg-allergy
6. Du Toit, G., Roberts, G., Sayre, P. H., Bahnson, H. T., Radulovic, S., Santos, A. F., … Lack, G. (2015). Randomized trial of peanut consumption in infants at risk for peanut allergy. New England Journal of Medicine, 372(9), 803–813. https://doi.org/10.1056/NEJMoa1414850
7.  Allergy & Anaphylaxis Australia. (n.d.). Peanut allergy. https://allergyfacts.org.au/allergy/peanut/
8. Allergy & Anaphylaxis Australia. (n.d.). Soy allergy. https://allergyfacts.org.au/allergy/soy/
9. Australasian Society of Clinical Immunology and Allergy. (2023). Dietary guide – shellfish allergy. https://www.allergy.org.au/patients/food-allergy/ascia-dietary-avoidance-for-food-allergy/shellfish
10. Allergy & Anaphylaxis Australia. (n.d.). Wheat allergy. https://allergyfacts.org.au/allergy/wheat/
11. Ierodiakonou, D., Garcia-Larsen, V., Logan, A., Groome, A., Cunha, S., Chivinge, J., … Hutcheon, J. (2016). Timing of allergenic food introduction to the infant diet and risk of allergic or autoimmune disease: A systematic review and meta-analysis. JAMA, 316(11), 1181-1192. https://doi.org/10.1001/jama.2016.14165