Introducing allergens safely when weaning your baby
Updated: 22 hours ago
Weaning is an exciting step, but for many parents it comes with a nervous question: how do I introduce foods like egg and peanut without causing a reaction? It is a fair worry. The reassuring news is that current evidence has changed how we think about this, and there is a calm, sensible way to go about it.
Why introducing allergens early can help
For years, parents were told to hold off on common allergy foods. The advice has now changed. Research, particularly for egg and peanut, shows that introducing these foods rather than delaying them can help reduce the chance of a child developing an allergy. So once your baby is ready for solids, usually around six months (and never before 17 weeks), these foods can be part of the journey.
The common allergens to include
The foods most often linked to allergy are:
Cow's milk (in cooking)
Egg
Peanut (as smooth peanut butter or a thinned paste, never whole nuts)
Tree nuts (ground or as a smooth butter)
Soya
Wheat and other gluten grains
Fish and shellfish
Sesame
How to do it safely
A few simple principles make this much less stressful:
Introduce one new allergen at a time, so if there is a reaction you know the cause.
Start with a small amount, then build up over a few days if all is well.
Offer new allergens earlier in the day, not last thing at night, so you can watch your baby.
Once a food is in and tolerated, keep offering it regularly as part of their usual diet. Regular exposure seems to be important for keeping the benefit.
Always make foods safe for the age: smooth, soft and never a choking risk.
For a practical step-by-step guide, see How to Introduce Egg and Peanut to Your Baby.
What a reaction can look like
Most reactions are mild: redness around the mouth, a few hives, or a bit of tummy upset. Watch for anything more serious such as swelling of the lips or face, widespread hives, vomiting, or any difficulty breathing. If you ever see breathing problems or floppiness, treat it as an emergency.
Extra care for some babies
If your baby already has moderate or severe Eczema, or a known food allergy, they have a higher chance of other allergies. It is worth getting tailored advice before you start, rather than holding back out of worry.
Feeling confident about weaning
You should not have to feel anxious at every mealtime. A nurse-led consultation can talk you through a step-by-step weaning plan that suits your baby, so you can introduce these foods with confidence, alongside your GP and health visitor.
What we do and do not provide
Allergy Nurture Nurses is a CQC-registered, nurse-led allergy and allergy-triggered Asthma advisory service for children, young people and families.
We provide assessment through taking an allergy-focused history, education, support and practical guidance. We do not provide emergency medical care, allergy testing, medical diagnosis or prescribing. Where appropriate we can liaise with the patient's GP and signpost to appropriate services. Where further medical assessment is required, families will be advised to contact their GP, NHS services or an appropriate healthcare professional. In a medical emergency, call 999.
Your baby or child should remain under their GP, NHS team or relevant healthcare professionals for clinical diagnosis, medical treatment, prescribing and urgent care.
When should I seek urgent medical help?
Most allergy symptoms are not emergencies. However, allergic reactions can occasionally become serious very quickly.
Call 999 immediately if your baby or child develops difficulty breathing, significant swelling of the tongue or throat, becomes floppy, collapses, appears severely unwell or develops symptoms of Anaphylaxis.
Urgent medical advice should also be sought if your baby's skin appears significantly infected or your baby is becoming unwell. Urgent symptoms are not suitable for a routine consultation or online enquiry.
This blog is general guidance and not a substitute for medical advice. If your baby has severe Eczema or a known allergy, seek personalised advice first. Call 999 if your child has any difficulty breathing or a severe reaction.
About the author
Written and clinically reviewed by Catherine Neale, NMC Registered Children's Nurse and Clinical Nurse Specialist, and founder of Allergy Nurture Nurses. Catherine has over 25 years' nursing experience, including 7 years as a specialist allergy nurse, and is a member of the British Society for Allergy and Clinical Immunology (BSACI).
Last clinically reviewed: 28 September 2026.
