Egg Allergy in Babies: Introduction, Reactions and Allergy Clinics

Egg allergy is the most common food allergy in infants and young children in the UK, affecting approximately 1 in 50 children under the age of two. The good news is that most children outgrow egg allergy — around 70% will tolerate egg by age five — but the management in the meantime requires care, and understanding the nuances of egg allergy (particularly the distinction between baked and lightly cooked egg) makes life considerably easier.

How to Introduce Egg During Weaning

Current NHS guidance supports introducing egg as part of normal weaning at around six months of age. As with other allergenic foods, the evidence now favours early rather than delayed introduction.

Form for first introduction: The safest initial form is well-cooked egg — scrambled, hard-boiled, or in an omelette where the egg is cooked throughout. This is important because the proteins that most commonly trigger reactions (ovomucoid and ovalbumin) are partially denatured by heat, making well-cooked egg less reactive than runny or lightly cooked egg.

Starting out: Offer a tiny amount initially — a small piece of well-cooked egg white or yolk — and observe for one to two hours. If there is no reaction, you can offer a normal portion. If there is any reaction, stop and seek advice.

If your baby has eczema or a known food allergy: These babies have a higher risk of egg allergy. Speak to your GP or health visitor before introducing egg at home, as some may benefit from an allergy clinic assessment first.

Recognising an Allergic Reaction Versus an Intolerance

It is important to distinguish between a true IgE-mediated egg allergy and a non-IgE-mediated reaction or intolerance, as the management and outlook differ significantly.

IgE-Mediated Egg Allergy

This is the classic, immediate allergic reaction. Symptoms appear within minutes to two hours of eating egg and may include:

• Hives (urticaria) — raised, itchy, red welts anywhere on the body
• Swelling around the mouth, lips, or eyes
• Runny nose, sneezing, or itchy eyes
• Vomiting
• In severe cases: difficulty breathing, throat swelling, collapse (anaphylaxis)

If your baby has any of these symptoms after eating egg, do not offer egg again and speak to your GP.

Non-IgE-Mediated Egg Reaction

Some babies react to egg protein in a delayed fashion, typically two to 72 hours after ingestion. Symptoms tend to be gastrointestinal (diarrhoea, vomiting, bloating) or skin-related (worsening eczema). These reactions are less dangerous than IgE-mediated allergy but are still worth investigating with your GP. Management typically involves dietary elimination followed by a structured reintroduction under professional guidance.

Egg Intolerance

True egg intolerance (as distinct from allergy) is not immune-mediated. Symptoms are usually digestive and dose-dependent. This is less well-defined in infants than in older people.

Baked Egg Tolerance: What It Means and Why It Matters

One of the most important concepts in paediatric egg allergy is the distinction between tolerance of baked egg versus raw or lightly cooked egg.

When egg is baked at high temperatures for an extended period — as in a cake, biscuit, or muffin — the allergenic proteins are more thoroughly denatured. Many children with egg allergy can tolerate baked egg even when they cannot tolerate scrambled or boiled egg. Studies suggest that around 70–80% of children with egg allergy can safely eat baked egg.

Why this matters: If your baby can tolerate baked egg, a much wider range of foods — including many cereals, cakes, pastries, and breads — becomes available. More importantly, there is evidence that regular consumption of baked egg by children who tolerate it accelerates the development of full egg tolerance over time.

Assessing baked egg tolerance: This is ideally done under the supervision of a paediatric allergist or dietitian, often using a standardised muffin or cake challenge. Do not attempt to assess baked egg tolerance at home if your baby has had a significant reaction to egg — this should be done in a clinic with resuscitation facilities.

What Happens at an Allergy Clinic

The allergy clinic appointment will begin with a detailed history of what was eaten, the nature of the reaction, and how quickly it appeared. Testing will likely include a skin prick test (using egg white and egg yolk extracts), and possibly a specific IgE blood test.

Results will help the allergist:

• Confirm whether the allergy is IgE-mediated
• Assess the level of sensitisation
• Guide decisions about baked egg, lightly cooked egg, and raw egg
• Advise on how frequently to repeat testing (since egg allergy often resolves with age)

If baked egg tolerance has not been established, the clinic may conduct a supervised baked egg challenge during the appointment or arrange one separately.

Managing Egg Allergy Day to Day

Label reading: Egg is one of the 14 major allergens that must be clearly labelled on pre-packaged food in the UK. Watch for terms such as albumin, globulin, lysozyme, mayonnaise, meringue, and ovalbumin — all of which indicate egg content.

Hidden egg: Egg is used as a glaze on pastries, in pasta, and in some processed foods. When eating out, always declare the allergy to staff.

Nutrition: Egg is a valuable source of protein, fat, and several micronutrients. If your baby cannot tolerate any form of egg, a dietitian referral ensures their diet remains nutritionally complete.

Reviewing the allergy: Because most children outgrow egg allergy, it is typically reviewed annually by the allergy clinic. Repeat testing will indicate whether tolerance is developing, and a graduated reintroduction (moving from baked egg to lightly cooked to raw) is usually attempted over time.

The outlook for most babies diagnosed with egg allergy is positive. With the right support, many families navigate it successfully, and the majority of children will be eating egg freely by school age.