Food allergy and eczema

A picture of a woman who is injecting an epipen into her thigh

Eczema is one of the diseases of the ‘allergic march’ – the progression of allergic symptoms from eczema to food allergy, hay fever and asthma – but for most people that doesn’t mean it’s caused by underlying allergies. On this page, you can find out how food allergies and eczema are interlinked along with advice and support.

Can food actually cause eczema?

In a small minority of children with egg allergy, regularly eating baked goods containing small amounts of egg may drive low-grade, constant reactions leading to chronic eczema.

For instance, a primary-school child with egg allergy would usually refuse all whole eggs, such as scrambled, boiled, fried or poached eggs, but they might tolerate the small quantities of egg baked into cake and other sweet goods without showing obvious immediate symptoms – this pattern might lead to an ongoing eczema flare. This usually seems to happen with egg, rather than other foods.

A far wider range of foods can exacerbate eczema without an actual allergy. For instance, some foods such as fresh tomato, pineapple, citrus and other fruits are acidic on sore or dry, sensitive skin. Some foods, such as chilli spices, have a vasogenic amine response, which causes a ‘nerve-tingly’ effect or flush the skin.

Finally, some foods, such as tomato sauce, commercial baby foods, spices and food preservatives, can irritate dermatitis, causing non-specific skin inflammation and exacerbating eczema. It is fairly easy to avoid these foods without negatively affecting the diet.

How does eczema cause food allergies?

The immune system has a lot to learn in the first months of life. If eczema develops during this period, it may increase the baby’s risk of developing IgE-mediated food allergy. Egg allergy is the most common one in toddlers, with milk being the second most common. Both of these are often outgrown. However, nut, seed and fin fish (as opposed to shellfish) allergies often persist into adulthood.

When skin is healthy, it forms an effective barrier to water loss, infections and allergens. If the skin barrier becomes dry and leaky during early childhood, the angry inflammation of eczema calls immune cells to the skin and these recognise food allergens within the skin from the baby’s home environment.

If eczema is not optimally treated with anti-itch topical steroids, there are two risks: first, that the eczema will be worse and last for longer, but second, that the immune system ‘sees’ food allergens, such as egg and nuts through the impaired skin barrier.

We know that the more angry the eczema, and the longer it persists, the greater the likelihood of food sensitisation and food allergy. Unfortunately, the most common food allergens in the home, such as milk, become the things the child is most likely to become allergic to.

So, proactively treating eczema during infancy may help prevent food allergy. In fact, a trial is currently underway in Japan to see whether proactively treating eczema during infancy with topical steroid creams can do just that. It may also be important to wash food allergens off the hands before applying emollients, to protect your child against food sensitisation.

How does eczema cause food allergies?

If eczema is not optimally treated with anti-itch topical steroids, there are two risks: first, that the eczema will be worse and last for longer – but second, that the immune system ‘sees’ food allergens, such as egg and nuts through the impaired skin barrier.

How to spot a food allergy

Most food reactions are mild, with digestive or skin-related symptoms. Skin signs often involve swollen lips or eyelids, or hives (‘wheals’): lumps in the uppermost layer of the skin, sometimes pale or surrounded by a rim of redness. They usually last minutes or hours and feel itchy, occasionally with a burning sensation. Digestive reactions include vomiting, abdominal pain and diarrhoea. All of these symptoms can be safely treated with an antihistamine, such as cetirizine.

Symptoms include:

Skin reactions

Swollen lips or eyelids

Hives, wheals or lumps in the uppermost layer of the skin

Digestive reactions
Vomiting

Abdominal pain

Diarrhoea

It’s important to actively look out for signs of a more serious allergic reaction, as these can easily be missed. A food reaction involving any of these signs (could be anaphylaxis and indicates a medical emergency.

Read our FAQ’s below for advice on when to call 999 and more.

FAQ’s

If your child has a food reaction with these symptoms, this could be a medical emergency:

Airway signs - Coughing, hoarse voice or tongue swelling

Breathing difficulty - Wheezing, chesty sounds or heavy breathing

Circulatory signs - Pale skin, drowsiness or sleepiness

Administering adrenaline

The symptoms above are best treated with adrenaline, to help support the circulation and resolve breathing difficulty. If your child has a known allergy, you may be given a Jext or EpiPen to administer adrenaline yourself in case of an emergency. Adrenaline is very safe to use. The only side effects are a headache from boosting the circulation (unless you accidentally press the active end into your own thumb!)

Breastfeeding mothers sometimes avoid food allergens in their own diet because they believe that allergens secreted in their breastmilk may be driving their baby’s eczema. However, recent studies show that the concentration of cow’s milk protein in breastmilk is vanishingly tiny. Even the highest concentration of cow’s milk recorded in breastmilk equates to the baby receiving 0.01mg in a breastfeed.

So, maternal milk consumption is unlikely to be driving eczema in a breastfed baby. If you have cut out cow’s milk, you can safely reintroduce it into your diet to see whether this has any effect on your baby’s eczema.

Some young babies have eczema and increasing gut symptoms, such as vomiting, diarrhoea or blood in their poo, at the same time. If this happens at the time that you are introducing cow’s milk to their diet, it could be a sign of non-IgE milk allergy. However, these symptoms are also very common among babies who do tolerate cow’s milk. So, talk to a health professional before removing cow’s milk from your baby’s diet.

Eczema affects between one-fifth and one-quarter of all people growing up in the UK. Essentially, eczema is a dry, itchy rash, with scaling, rough patches or open, scratched areas of skin. The hands, face, neck, elbows, inside knees and torso are often affected in adults, while young children often develop eczema over their cheeks, ears, outer arms and thighs. In pale skin, the rash looks red. In darker skin, the redness can be harder to see, but the surface change, itching and disruption make eczema unmistakeable.

Eczema is caused by dry skin. If someone carries a filaggrin mutation, this acts like a broken waterproofing gene and makes them four times more likely to develop eczema. The skin is dry, which in turn makes itching and inflammation more likely, resulting in cycles of eczema flares and relative improvement before more flares. Sometimes, the open skin of eczema can become infected, wet and oozy. At that point, it is important to see a health professional to discuss urgent treatment.

Skin flares can be triggered by lots of different factors. Irritant detergents dry the skin further and remove natural moisturisers. Viral illness makes the immune system angry. Hot, synthetic or abrasive clothing causes irritation, too. Some foods, such as tomato juice, chocolate, preservatives or spices can inflame the skin, even though they are not causing allergies.

Food allergy is a hyper-sensitivity in the immune system triggered by particular food proteins. An allergy can always be duplicated – in other words, the same effect will occur every time someone eats a particular food.

THE TWO TYPES OF ALLERGIC REACTION

Immunoglobulin E (IgE) mediated allergy reactions are driven by IgE antibodies. They recognise the surfaces of food proteins (epitopes) within the allergen. They usually arise immediately after the food is eaten.

Non-IgE-mediated allergy reactions are slower, taking up to 48 hours to develop.

Find out more

DermNet - Use this site to compare rashes to pictures
BSACI - The UK’s leading healthcare organisation for healthcare professionals caring for patients with allergies
NHS - Use the NHS site for information on a range of conditions

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Living with eczema (for adults) booklet

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