Allergy and eczema

This page contains three allergy-related articles from our magazine, Exchange.

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Could food allergy be causing your child’s eczema?

Allergy to artificial nails

Tattoos and eczema

Could food allergy be causing your child’s eczema?

If social media were to be believed, almost any symptom can be cured by cutting out foods. Dr Tom Marrs, Consultant in Paediatric Allergy at St Thomas’ Hospital, Guy’s and St Thomas’ NHS Foundation Trust, helps us separate fact from fiction. This article was published in Exchange 181, September 2021.

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.

So, when should we consider whether food allergies are making our child’s eczema flare?

What is eczema?

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.

What is food allergy?

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.


  • 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.

How eczema is linked to food allergy

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 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.


• Swollen lips or eyelids
• Hives, wheals or lumps in the uppermost layer of the skin

• Vomiting
• Abdominal pain
• Diarrhoea

It is 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 the signs below (‘When to call 999’) could be anaphylaxis and indicates a medical emergency.

When to call 999

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!)

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.

Introducing cow’s milk in babies’ diets

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.

Find out more

  • for comparing rashes to pictures
  • BSACI The UK’s leading healthcare organisation for healthcare professionals caring for patients with allergy
  • NHS for information on a range of conditions

Allergy to artificial nails

Acrylates are used widely in a wide range of products and processes – from aircraft manufacturing to dentistry. In recent years, there has been a sharp increase in allergic contact dermatitis due to acrylates, driven by the explosion in nail bars. Dr Sophie Rolls, dermatology specialist registrar at Cardiff and Vale University Health Board, explains. This article was published in Exchange 177, September 2020.

Artificial nails

Acrylates have long been recognised as a common cause of allergic contact dermatitis (ACD). However, recently there has been a striking increase in sensitisation to acrylates across the UK and Europe, and further afield, in Singapore and the United States. In 2012, the American Contact Dermatitis Society named acrylates Contact Allergen of the Year and has since included acrylates in the US baseline patch test series.

The increased frequency can be explained by a shift in occupational and recreational exposure – away from traditional industries associated with acrylate allergy, such as dentistry, and towards the beauty industry, where there is soaring demand for nail fashion with UV-cured gel, shellac nails and glue – all of which contain acrylates.


  • ACRYLATES are chemical molecules or monomers that bind together in a process called polymerisation to form acrylic plastics. Their use is widespread: from the graphic and printing industry to aircraft manufacture, orthopaedic cement, surgical glue, dressings, dentistry – for example, in white fillings set under ultraviolet (UV) light – and, more recently, in nail fashion. In this article, we refer to them throughout as ‘acrylates’.
  • ALLERGIC CONTACT DERMATITIS is a form of eczema caused by an allergic reaction to a substance, known as an allergen, in contact with the skin. The allergen is harmless to people that are not allergic to it. Allergic contact dermatitis is also called contact allergy.

How is it caused?

ACD is a delayed hypersensitivity reaction. In ACD, a person’s immune response is induced by a particular sensitising substance, known as a ‘contact allergen’ – in this case, an acrylate monomer. The first phase is called sensitisation, or induction. At this stage the person becomes immunologically sensitised although they show no symptoms. When the person is re-exposed to the same substance, or something that reacts with it, this triggers the next phase: elicitation. This activates an individual’s immune system and symptoms become apparent.

The appearance of ACD will depend on which area is affected. Unsurprisingly, ACD to acrylates is most commonly seen on the fingertips and nails.

Symptoms can include:

  • NAIL DYSTROPHY distortion and discoloration of normal nail-plate structure
  • ONYCHOLYSIS loosening or separation of a fingernail or toenail from its nail bed. This usually starts at the tip of the nail and progresses back
  • HYPERKERATOSIS thickening of the nail
  • FISSURING and SPLITTING of the fingertips and inflammation of the nail fold.

Symptoms may be found not only around the nail area but also in areas that are commonly touched, such as the eyelids, mouth, chin and sides of the neck. However, uncured acrylate monomers can cause symptoms anywhere on the body that they touch. Symptoms include patches of streaky, red, tight, dry and itchy skin, characteristic of eczema. Diffuse eyelid eczema is also often seen in ACD to nail enamels and removers.

Who’s at higher risk?

Acrylate monomers are a well recognised cause of ACD. However, people with atopic eczema are at higher risk of ACD since their skin barrier is damaged, which increases the penetration of allergens and irritants (substances that causes irritation). In some cases, it can be difficult to distinguish between ACD and atopic eczema.


Once someone becomes sensitised to acrylates, their symptoms will persist, as long as they use acrylic nails and glue containing these allergens. The symptoms can be alleviated with standard eczema treatment, such as soap substitutes, emollients and topical corticosteroids. However, the definitive treatment is to avoid the offending allergen.

There are many acrylate allergens. If someone has suspected allergy to acrylic nails, they can identify which allergen they are sensitised to through patch testing by a dermatologist to the (meth)acrylate series. However, even if an individual is allergic to just one single acrylate – for example, 2-hydroxyethyl methacrylate (the commonest acrylate that people are sensitised to) – it is best to avoid acrylates altogether.

This is because acrylates are known to crossreact. This means that a person who is allergic to one acrylate may be sensitised to other acrylates since they all have similar chemical structures. Also, acrylic nail products contain a number of different acrylate allergens, which can cause concomitant sensitisation, and this makes it is difficult to identify the exact allergen to which an individual is sensitised.

Application and removal process

The step-by-step nail application and removal process highlights the many points at which someone can become sensitised to acrylates:

  1. First, the consumer chooses their colour from an expansive array.
  2. The nails are filed and shaped. The cuticle, which is a protective seal, is pushed back and removed and therefore damaged.
  3. A primary layer of gel polish containing acrylate monomers (the active allergen) is applied to the nails and each hand is then placed underneath the UV lamp for 30 seconds, allowing time for the active acrylate monomers to polymerise into their inactive form.
  4. This cycle is repeated until two coats of colour and a finishing coat are completed.
  5. The removal process involves filing the nails, soaking them in acetone for 15 minutes – which is highly irritant – and then scraping off the gel polish.
  6. Acrylic nails are then frequently re-applied.

There are many points at which an individual can become sensitised to acrylates during the application and removal of acrylic nail fashion.

NAIL TRAUMA Because the nail is traumatised in the application and removal process, any uncured monomers can easily penetrate the broken cuticle, nail fold or damaged skin barrier.

SKIN CONTACT If any skin is touched by a nail coated with uncured acrylate monomers, these monomers can be transferred to the skin and cause sensitisation.

Many gel polishes require a specific UV or LED lamp to ensure the acrylate monomers are polymerised. If there is a mismatch between the gel polish and the lamp, or the hands are placed under the lamp for the incorrect amount of time, not all the monomers will be polymerised into their inactive form, or ‘cured’. A nail with uncured monomers carries a risk of sensitising wherever it touches.

It is important that this is accurately diagnosed so that the person understands to avoid acrylate allergen, since allergy to these chemicals can have lifelong consequences – such as avoiding future dental treatments and surgeries containing acrylates.

Nail technicians

Nail technicians are at high risk of occupational exposure to acrylates. The more you are exposed to an allergen, the more likely you are to become sensitised. Nail bars are ubiquitous on every high street and nail technicians are often young people working in poor – sometimes slave-like – conditions, as highlighted in media reports. Nail technicians are often inadequately trained on the correct use of personal protective equipment and the potential health risks associated with acrylates.

To tackle the problem, there have been calls for increased regulation, better training and personal protective equipment for nail technicians, along with better labelling and a national registration process to monitor growing popularity of artificial nail fashions and surveillance on the incidence of sensitisation – particularly among consumers using kits at home.

In an attempt to protect workers, the Hair And Beauty Industry Authority (HABIA) has produced a code of practice for the nail industry. This includes wearing nitrile protective gloves. The Health and Safety Executive, too, outlines health and safety in nail bars. Premises in the UK providing manicures and nail extensions are required to be registered under ‘massage and special treatment premises licensing’ – but this is overseen on a regional basis by local authorities, and criteria vary. Any increase in future incidence of sensitisation should be kept under surveillance.

Alternatives to nail gel

Unfortunately, all nail enamels – including removers and artificial nails – contain allergens to which people can become sensitised. The most common is tosylamide formaldehyde resin. Hypoallergenic nail enamels that use polyester resin or cellulose acetate butyrate may be an alternative, but sensitivity is still possible, and they are less durable and scratch resistant.

Limit your risk

  • Manage eczema as normal with your maintenance therapy.
  • If you work in the beauty industry, make sure you understand the risks and that your employer provides you with adequate training, nitrile gloves and face masks. If symptoms persist, you may need to consider changing profession.
  • Always read instructions carefully for UV lamps.
  • If your eczema is resistant to your usual treatment and you are in contact with acrylates, consider the possibility of ACD. Contact your GP who can organise a referral for patch testing.

Tattoos and eczema

This ‘Ask the Expert’ article was published in Exchange 186, Winter 2022.

Q I’m 19 and planning to get a pretty big tattoo on my arm but I’m nervous about this kicking off an eczema flare-up. Does eczema get worse on the skin where you have tattoos?

Helen Dennis, Dermatology Nurse Adviser to NES, says: Tattoos are very popular, but they do carry some risks. We don’t know whether these are significantly higher for people with eczema. It is likely to depend on how severe your eczema is and your risk of contact allergy. Tattoos can certainly trigger eczema flares, and the eczema can get worse where the tattoo is, but many people with eczema have tattoos without problems.

One thing to consider is the risk of infection due to scratching. This is worse immediately after the tattoo but also days and even months later. The signs of infection include deepening redness/ darkening, pain worsening and not subsiding, pus in the tattoo and open sores developing. If you see any of these signs, go to the doctor immediately, as the sooner you start treatment the better for your health and for the tattoo.

Another possibility is allergic reaction triggered by the dye or ink. Some people have experienced this delayed reaction even decades later, linked to joint replacement surgery or starting treatment for HIV. There are many dyes used in tattooing and the tattoo artist may have preferences for people with sensitive skin. For example, black henna tattoos can be dangerous if you are allergic to paraphenylenediamine (PPD) – and most people do not know if they are allergic. A patch test is no guarantee the procedure will be problem free.

Besides eczema, there are other skin issues reported with tattoos. Some people develop a
‘sun allergy’. To protect your tattoo, use a high SPF (30 or more) when outdoors and cover it with clothing in bright sunlight. You also need to think about how your skin scars. If you have a tendency for keloid scarring, developing keloids in the tattooed area is a real possibility. There have also been rare reports of burns to tattooed skin during MRI scanning. So, if you have an MRI for any reason, it is important to flag any tattoos to the radiographer.

Finally, tattoos are permanent, and (at the risk of sounding like your parent!) the way you think when you are 19 is likely to be different when you are 25 or 30. ‘Tattoo removal’ techniques don’t actually offer complete removal: they blur the image but still leave a visible mark in the skin. So, there’s a lot to consider. Tattoos can look great, but taking this step is a big decision and there is no need to rush it, so take your time.