Food allergies in children: your FAQs answered by a specialist

Written by: Professor Adam Fox
Published: | Updated: 06/03/2019
Edited by: Emily Lawrenson

Food allergies in children are becoming increasingly common, with the number rising as time goes by. Food allergies, which 30 years ago were considered unusual, are now becoming more widespread, affecting an estimated 5-6% of young children and 1-2% of adults.

Nowadays it seems that we all know someone who has a food allergy, and if you have a history of allergies in the family, it’s natural that you might worry about your child developing one themselves. The good news is that as the numbers increase, so does our awareness – but it’s important to know what the red flags are, and what to watch for, giving you an idea if the symptoms indeed point to an allergy. Dr Adam Fox, a leading paediatric allergist from Allergy London, is here to answer some of the most frequently asked questions about food allergies in children.

1. Are allergies genetic?

Specific allergies themselves are not inherited, but the tendency to develop allergies and allergic problems (e.g hay fever, asthma, eczema) can be inherited from one or both parents. Just because you are allergic to shellfish, for example, does not mean that your child will be automatically, but it does mean that they have a chance of inheriting an allergic tendency. There is also the chance that a child will develop an allergy with no genetic link, as allergies may also be influenced by environmental factors.

2. My child has eczema, should I be worried about a food allergy developing?

All atopic diseases (hay fever, asthma, eczema, food allergies) are related to one another, and food allergies are most common amongst babies who have eczema. Children who are atopic often go through a process we call the ‘allergic march’, which is a progression of the related conditions. This often starts with eczema when very young, which predisposes food allergies. Children often outgrow their eczema and food allergy, but on occasion these conditions can give way to respiratory allergy, such as hay fever or asthma.

Read more: Childhood asthma

3. What are the most common food allergies in children?

The most common types of immediate reaction food allergy are egg, milk, nuts, fish, sesame and shellfish. Soy, wheat, and kiwi are also rather frequent, but for delayed type allergies (where symptoms are not seen immediately after the food is ingested), the most common culprits are milk and soy.

4. What’s the difference between an allergy and an intolerance?

A food allergy causes an immune system reaction which can affect various organs in the body. Food allergies can be serious and a reaction can be life-threatening. Intolerances, on the other hand, are generally less serious and are more often related to problems digesting food. There are two types of allergy, the first being immediate allergy, which causes rash, swelling, and hives to develop within minutes of the food being eaten, and delayed allergies. Delayed allergies can cause eczema to develop, or symptoms such as reflux, colic, and diarrhoea – the latter three sometimes being seen as symptoms of intolerance, too. If you are worried about any of these symptoms or notice them in your child, you should visit your GP.

5. If my baby is allergic to one food, will they also be allergic to others?

It’s true that having one allergy often increases the risk of other allergies being present or developing. Certain allergies are commonly experienced together, for example egg and peanut, or peanut with treenuts and sesame.

6. If I eat nuts while pregnant, is there a chance my baby will develop an allergy?

There is no need to avoid nuts during pregnancy, or while breastfeeding. Eating nuts during this time has no influence on your baby developing a nut allergy.

7. Is there any way to protect my baby from developing an allergy?

Avoiding certain foods during pregnancy or while breastfeeding does not seem to make any difference in the chances of your baby developing an allergy. Aim to breastfeed, if possible, for six months exclusively. Evidence is beginning to emerge that introducing complementary foods, in particular eggs and peanut, from 17 weeks onward, may be helpful in protecting against allergies to these foods developing.

8. Will my baby outgrow their allergy?

This sometimes depends on the allergy. Fortunately, children tend to outgrow allergies to milk, egg, soy, and wheat. On the other hand, allergies to peanuts, treenuts, fish, and shellfish tend to continue through to adulthood.


Learn more about Dr Fox and Allergy London on his Top Doctors profile. If you are interested in discussing your child’s allergy symptoms and learning more about allergy testing, make an appointment with a specialist.

By Professor Adam Fox
Allergy & immunology

Professor Adam Fox is an expert consultant adult and paediatric allergist and immunologist and one of the founding consultants of the children's allergy service at the world-renowned Guy's and St Thomas' Hospitals, home to the UK's largest paediatric allergy centre. Professor Fox is one of only a handful of UK doctors with recognised higher specialist training in paediatric allergy. His specialist interests include the management of food allergies, eczema, asthma, rhinitis (including hay fever), conjunctivitis, and drug and insect sting allergy. From 2018 to 2021, he held the position of president of the British Society for Allergy and Clinical Immunology, having become the first paediatrician to be elected into this role. Professor Fox remains a trustee of the organisation. In July 2022, he became the chair of the National Allergy Strategy Group, which involves working closely with the Department of Health and Social Care.  

Professor Fox completed his clinical training at University College London, having read Medicine and Neuroscience at Cambridge University. He went on to complete specialist training in paediatric allergy in 2006, before spending nine years as clinical lead of allergy at Guy's and St Thomas' Hospitals, London; one of Europe's largest specialist allergy services, recognised as a Centre of Excellence by both the World Allergy Organisation and GALEN (European Asthma and Allergy Network). Following three years as clinical director for specialist ambulatory medicine, he began as commercial medical director for Guy's and St Thomas' Hospitals NHS Foundation Trust. In 2021, with two of his colleagues, he established The Food Allergy Immunotherapy Centre at Great Ormond St Hospital. It was here, where Professor Fox administered the first patient outside of the US Palforzia, the first licenced food allergy desensitisation product.  

In addition to his clinical work, Professor Fox has conducted extensive research and is actively involved in cutting-edge research in allergy desensitisation, asthma prevention, and food allergy, in setting up the largest allergen desensitisation programme in the UK. He has also published extensively and is the senior author of the Milk Allergy in Primary Care guideline, which has been adopted around the world and received the Allergy UK Innovation Award in 2018. Professor Fox is a professor of paediatric allergy at King’s College London, the founding director of the KCL Allergy Academy, an advisor to the National Institute of Healthcare and Clinical Excellence (NICE), and chaired a clinical guideline development group for food allergy in children. Professor Fox has lectured internationally, been involved in the production of various documentaries, and has frequently appeared in TV and print media, notably as a regular contributor to ITV’s ‘This Morning’. 
As a result of his extensive experience and expert care, Dr Fox was included in The Times' Magazine ‘Britain's 100 Best Children's Doctors’, with the Tatler 2013 Guide listing him as one of the UK's top 250 specialists. In 2007, he was recognised as 'Paediatric Allergist of the Year' by Allergy UK. He also received the Raymond Horton-Smith award from Cambridge University for his research in 2012 and a national Clinical Excellence Award from the Department of Health in 2016 and 2020. In 2016 he was awarded the William Frankland Award from the British Society for Allergy & Clinical Immunology for his contribution to the speciality. In 2018, he earned an Excellent Patient Experience from Doctify and was one of the 29 specialists to be honoured with a ‘Top Doctors Award’ from Top Doctor, voted for by other specialists.   

Allergy London, Professor Fox’s private practice, was awarded Best Allergy Clinic in London in the Global Health & Pharma Private Healthcare Awards (2019) and Best Allergy Testing Specialists in the Private Healthcare Awards (2020). On Trustpilot, the practice has a 4.9/5 rating.  

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