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What causes eczema

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In this article

Is eczema an autoimmune disease
Is eczema infectious?
Is eczema genetic?
Can you develop eczema later in life?
The difference between causes and triggers
Internal causes of eczema flare ups
External causes of eczema
Lifestyle factors and eczema flare ups?
Topical products and eczema
Sunscreens causing eczema
Environmental factors and eczema flare ups?
Can antibiotics cause eczema?
What causes eczema to flare up?

Eczema is a skin condition characterised by red, dry, itchy, sometimes cracked and weeping skin. It can affect anyone at any age and there are a number of causes.

One of the most common forms of eczema types is contact eczema, also referred to as contact dermatitis. There are two types of contact dermatitis – irritant contact dermatitis and allergic contact dermatitis.

Irritant contact dermatitis is caused by an irritant touching the skin and causing a reaction. Common irritants include soaps, industrial chemicals and even strong, cold winds.

Allergic contact dermatitis is caused by an internal immune system reaction to something coming into contact with the skin externally. Common allergens include nickel that is used to plate jewellery and watches, perfumes and hair dyes.

Another common form of eczema is atopic eczema. Atopic eczema is caused by genetics and often runs in families. Flare ups can be triggered by exposure to irritants or allergens and also substances such as animal fur and house dust mite droppings.

Is eczema an autoimmune disease

Doctors and researchers are still debating whether or not eczema is an autoimmune disease. There is some evidence that it is, and that drugs that work on the immune system can also work to treat eczema.

Studies continue to find an exact link between eczema and the immune system.

Is eczema infectious?

You may be concerned that your eczema is contagious to others. But it isn’t possible to pass eczema on to someone else, even if you currently have a severe flare up of eczema and you touch someone’s skin.

However, infected eczema, caused by a bacteria or a fungus getting inside broken skin caused by eczema can cause an infection in someone else’s skin if they have an open wound or broken skin caused by either eczema or something else.

Infected eczema looks redder and more inflamed than non-infected eczema. It can also feel hot to the touch or painful and can ooze a colourless or yellowy green discharge.

Is eczema genetic?

Certain forms of eczema are hereditary meaning that if a close family member has eczema then you have a higher risk of also having the condition.

This is especially the case with atopic eczema, which often develops in young children or babies and continues through adulthood.

Can you develop eczema later in life?

It’s common to develop eczema as a baby and for it to continue to affect you throughout your life. But it’s also possible to develop eczema as an adult.

Some people develop eczema in their early teens, some develop it in their 30s, 40s and even beyond that.

The difference between causes and triggers

Whilst having eczema is caused by irritants, allergens and genetics, there are a number of factors that can trigger flare ups.

This means that a trigger such as sweating might cause a flare up, but it hasn’t actually caused you to have eczema in the first place.

There are numerous triggers for eczema and individuals react differently to different substances.

Here, we discuss these triggers so that you can decide whether or not they might be causing your eczema to flare up.

Internal causes of eczema flare ups

What causes eczema? Here are some common internal triggers for eczema:

Allergies that can cause eczema

Certain allergens that can cause eczema to flare up include tree and weed pollen (that also case hay fever), house dust mite droppings, mould spores and the hair, fur and skin cells (called dander) from cats and dogs.

Can hormonal imbalance cause eczema

Our hormones are fluctuating all the time, particularly so in women around the time of their period or if they’re pregnant or approaching their menopause. These hormonal imbalances are difficult to control and can mean that they cause eczema symptoms to feel worse.

30% of women find their eczema flares up in the days before their period. A hormonal imbalance can be caused by multiple factors many of which are difficult to control. But having an understanding of how hormonal fluctuations can affect your skin may help.

This explains why your eczema may flare up before your period, if you’re pregnant or breastfeeding, or going through your menopause. Being on the contraceptive pill can also potentially cause eczema flare ups as it can cause a surge in hormones.

Can thyroid problems cause eczema?

If you have an underactive thyroid, a condition called hypothyroidism, it may be leading to more frequent eczema flare ups.

Researchers think this may be connected to an imbalance in thyroid hormones which can affect the skin. Talk to your thyroid or skin specialist if you think your eczema is triggered by your thyroid problem.

Does a leaky gut cause eczema?

A leaky gut means that the thin mucous membrane barrier between our intestines and the rest of the body is damaged. This can mean that toxins and partially digested food can leak from the gut into the bloodstream and can then reach the skin.

The evidence for the connection between a leaky gut, gut disease in general and eczema is unclear currently. But research continues into this connection and how it could be important in the long term treatment of eczema.

Can diabetes cause eczema?

There is currently no evidence to suggest that diabetes can trigger eczema symptoms. But if you think diabetes could be causing your eczema symptoms to feel worse, speak to your GP or specialist.

Is eczema caused by a virus?

Eczema itself isn’t caused by a virus, but viruses, and bacteria and fungi, that live naturally on the skin can cause infected eczema.

Natural skin microorganisms don’t usually cause problems, but if your eczema is very bad and scratching it has caused the skin to become broken or cracked, these viruses, bacteria and fungi can colonise the open skin causing an infection.

If your eczema is infected, it will become more red, hot to the touch, painful and / or weepy with a clear or yellowy green liquid.

Can lupus cause eczema?

Lupus is an immune system condition that means the body can mistakenly attack healthy tissue. It can cause areas of skin to become red, itchy and scaly in a condition called discoid lupus.

This can be mistaken for eczema as they cause similar skin complaints, but they are very different conditions.

Can a lack of vitamin D cause eczema?

There is evidence to suggest that taking a vitamin D supplement can help some people manage their eczema symptoms.

It’s thought that many of us living in the UK are deficient in vitamin D, especially in the winter months when sunlight is low (the skin makes vitamin D by absorbing sunlight). Try taking a daily vitamin D supplement for two or three months to see if it makes a difference to your skin.

External causes of eczema

Just as with internal factors, there are some external factors that can cause eczema prone skin to become worse. Here's our eczema tips

Can stress make eczema worse?

Flare us of eczema caused by stress is a common phenomenon but doctors cannot definitively say why. Many people report that stress can make their eczema worse, so however the two are linked, staying as stress free as possible is key.

But we appreciate staying stress free is difficult! Tips for managing stress include getting plenty of rest, talking to peers, colleagues and loved ones about how you feel and practicing mindfulness techniques.

Being stressed can also mean that you mindlessly scratch at your skin more often, so try to be aware of this. If you find you scratch your skin when you’re asleep, try wearing cotton gloves in bed and make sure you keep your fingernails short.

Can food cause eczema flare ups?

If you have a food allergy, you’re more likely to also suffer with eczema. An allergy to a certain type of food won’t directly cause eczema, but food allergies can cause eczema flare ups. Unlike something that you put on your skin that can cause irritation, it can be very difficult knowing what foods may cause your eczema flare ups.

This is because it can take a few days to have an effect and by then, you won’t know which food has caused it. However, here’s a list of common foods that can cause allergies and eczema flare ups.

Your doctor can help you if you wish to try an elimination diet to help you work out which foods might be your triggers. It’s not advised that you embark on an elimination diet and remove whole food groups from your diet without proper medical supervision.

Food intolerances and eczema

Eczema can be triggered by an allergic response to food. If we eat a food that our body cannot tolerate, we develop an allergic response. The substance causing the allergic reaction can cause this allergic response in the skin as well as the gut.

In the skin it can cause the classic itching, dryness and irritation of eczema. In our gut we might experience bloating, pain, nausea and diarrhoea.

We all react to foods in different ways - a food that can be tolerated by one person might not be tolerated by another. If you have eczema prone skin, it’s important to gain an understanding of your personal intolerances and the effects different foods have on your body. That way you can make the right choices and eliminate the trigger foods from your diet.

Digestive problems and eczema

Our gut is lined with a thin mucous membrane consisting of a thin layer of cells. This membrane is the barrier between the inside of our gut and the rest of our body.

When we have digestive problems such as irritable bowel syndrome or Crohn’s disease, toxins, bacteria and unwanted food particles can cross this barrier and enter the blood stream. This can cause inflammation throughout the body and trigger a reaction in our skin leading to eczema.

Can a gluten or wheat allergy cause eczema?

There is a small risk that having a gluten allergy called coeliac disease can make eczema symptoms worse. Doctors think coeliac disease and itchy skin may be due to a genetic link but at the moment they can’t be sure.

If you have a gluten or wheat allergy or intolerance, it may be worth speaking to your specialist about how it could be affecting your eczema.

Does dairy cause eczema?

A lactose intolerance can also cause eczema symptoms to become worse. If you’re lactose intolerant or you have a dairy allergy, it may be causing your eczema to flare up. Thankfully now there are plenty of dairy free milt, yoghurt and cheese alternatives on the market.

Can sugar cause eczema?

In some people, eating too much sugar can lead to eczema flare ups. This is because overloading the body causes unnatural spikes in insulin levels which in turn causes a rise in inflammation in the body. Inflammation can cause eczema symptoms to feel worse.

Can avocado cause eczema?

Avocadoes are touted as the ultimate health food, but there are some people who say that eating avocadoes causes their eczema to flare up. It’s not understood why, but it may be something that you can easily remove from your diet for a few weeks to see if doing so makes a difference to your skin.

Can oatmeal cause eczema?

If you have a gluten allergy, then some oats are off limits for you. Whilst oats don’t actually contain gluten, they’re often grown in fields next to wheat which can contaminate oat products with gluten. Eating oats can therefore trigger your eczema symptoms.

But oats can cause eczema symptom flare ups as a result of another protein in them called avenin. It’s not common to be sensitive to avenin, but people that are can experience worse symptoms of eczema after eating oats.

Can olive oil cause eczema?

Natural plant oils such as olive oil are often used to help reduce the symptoms of skin conditions such as eczema. But in some people with eczema, olive oil can actually make their skin worse.

It’s thought that this is because olive oil has relatively low levels of substances called oleic acid and linoleic acid. These low levels have the opposite effect of hydrating the skin and can instead damage the upper layers of the skin causing eczema symptoms to feel worse.

It’s thought that cooking with olive oil or using it to dress salads is fine. But if you have eczema prone skin, avoid applying it directly to your skin.

Can chicken cause eczema?

Whilst eating chicken cannot itself cause eczema, some people with an allergy to chicken do report that as well as causing itchy, swollen eyes, a runny nose, scratchy throat, wheezing and vomiting, it can cause their skin to itch. If you have eczema prone skin, eating chicken could therefore cause your skin to feel worse.

Can tomatoes or lemons cause eczema flare ups?

Some people find that eating tomatoes or citrus fruits can cause their eczema symptoms to become worse. Symptoms are often immediate and include skin rashes, itching, swelling and redness. There are also people for whom simply touching the tomatoes or the juice from a lemon can cause immediate eczema symptoms.

Do nuts cause eczema?

Nuts are also known to cause eczema flare ups in some people with nut allergies. If you have a nut allergy, you will know which nuts to avoid. This will also help to support your skin as well as being potentially lifesaving.

Can garlic cause eczema?

Having a garlic allergy can lead to wheezing, itchy eyes, a runny nose and itchy inflamed skin, especially if you also suffer with eczema. You may also find that you’re sensitive to onions, leeks, shallots and chives, too.

Can tea cause eczema?

Black tea can contain traces of nickel, which can cause allergic contact eczema symptoms to flare up.

Can drinking alcohol cause eczema?

It isn’t common for alcohol to directly cause eczema flare ups, but drinking alcohol to excess on a regular basis leads to dehydration and increased levels of inflammation in the body.

Both dehydration and inflammation can affect the skin and if you suffer with eczema, you may find your symptoms feel worse after drinking alcohol.

More specifically, drinking wine made from grapes can case eczema flare ups, even in small quantities. This is because grapes are rich in substances called salicylates and amines which can trigger itching in the skin.

Can water cause eczema?

Being in constant contact with water, say for your job, can cause contact eczema to become worse. But simply showering in water that’s too hot can also lead to a flare up of symptoms.

Also, living in an area with very hard water can also have an impact on your skin. As can living in an area with highly chlorinated water. Your local water company will be able to help you work out if your water is very hard or chlorinated.

If so, and you think that your daily shower could be making your eczema worse, then take short showers and avoid bathing (and swimming). You can also buy water softeners and dechlorinating showerheads that attach to your taps and showers that can also help.

Is eczema caused by a fungus?

Eczema itself isn’t caused by a fungus or a bacteria, but fungus and bacteria can cause eczema patched to become infected.

A normal skin bacteria called Staphylococcus aureus thrives on oozy, weepy or inflamed skin and commonly infects the broken skin caused by eczema. It’s also common for eczema to become infected by a fungus, especially on the skin folds such as behind the knees where the skin can become warm and damp.

You will know your eczema has become infected because the affected areas will become more red, hot to the touch, blistered, painful and / or will weep a colourless or yellowy green discharge.

Lifestyle factors and eczema flare ups?

There are certain lifestyle factors that can make eczema symptoms worse. These include smoking and doing things that cause you to sweat excessively.

Can smoking cause eczema?

Doctors are unsure exactly why, but smoking, or living in a house with a smoker, can make eczema symptoms worse.

Smoking is bad for all aspects of our health so speak to your doctor or pharmacist for advice on quitting smoking if you’re struggling to give up.

Can sweating cause eczema?

If you have eczema, spending time outside in strong sun can cause prickly heat, where your skin feels hot and prickly.

This is caused by excessively sweating and can also be brought on by being too hot in bed, wearing too many clothes or by taking part in high intensity exercise. Long, hot baths and showers can also cause eczema prone skin to feel worse.

Topical products and eczema

Many every day products that come into contact with your skin either by applying them or by accident can cause eczema flare ups. These include soaps, washing up liquids, cleaners and other detergents as well as certain shampoos, shower gels and bubble baths.

Shaving can also cause eczema flare ups. If you’re shaving your face, legs, bikini area or anywhere else that suffers with eczema flare ups, always use a sensitive skin razor and replace it often – blunt blades will cause more irritation to the skin. Make sure you use a shaving cream that lathers up properly and always moisturise afterwards.

Certain types of makeup can cause eczema symptoms to flare up and the fragrances used in some perfumes can also trigger eczema flare ups. Opt for hypoallergenic makeup that’s perfume free and try not to wear perfume.

Even some products that are supposed to be nourishing for the skin such as Argan oil and coconut oil can cause eczema flare ups if you’re allergic to them. Argan oil benefits are sometimes plentiful so it's trial and error. 

Working out what topical products may be causing your eczema to flare up may be a long and arduous task, but you will benefit from avoiding them in the long run – so it’s worth doing the hard work!

Sunscreens causing eczema

Chemical sunscreens that work by absorbing UV light from the sun can irritate sensitive skin that’s prone to eczema.

If your eczema is affected by sun protection products, look for more natural sunscreens called mineral sunscreens. These work by physically blocking the sun’s rays by using ingredients including zinc oxide and titanium dioxide. They’re less likely to irritate your skin as they don’t contain harsh chemical ingredients.

Environmental factors and eczema flare ups?

As we mentioned above, there are many allergens that can trigger a worsening of eczema symptoms.

These include certain things in your environment including the hair, fur and skin cells (dander) from cats and dogs which can all trigger eczema. Dust itself doesn’t cause eczema but the droppings from the house dust mites that happily live in house dust can. Regularly using a vacuum cleaner with a strong HEPA filter will help.

Bed bug droppings can also aggravate eczema so using allergy bed linen and washing it on a high heat regularly will also help. Mould spores can also trigger eczema flare ups so make sure you clean any mould patches that appear in places such as your bathroom or around your windows.

Not having pets in your home and keeping your home as clear of dust and mould spores as possible will help if they’re triggers for you.

Can antibiotics cause eczema?

There is some evidence that taking certain antibiotics, particularly in childhood can lead to eczema symptoms getting worse, but as yet there is no conclusive evidence.

What causes eczema to flare up?

As we can see here there are many things that can cause eczema flare ups in adults and children. Any of these causes can mean that your eczema can flare up anywhere on your body or face.

Some things may cause eczema to become worse for you yet may be totally fine for someone else. Understanding your own triggers can help you understand why eczema can come and go and will help you avoid your eczema breakout causes.

It can be a long and painful process working out what causes your eczema to flare up but once you do, you can help to effectively support your eczema prone skin.

Hannah de Gruchy BSc(Hons)

About Author

Hannah de Gruchy is a freelancer writer who specialises in health and wellness. She has a keen interest in the biology of skin and loves using her words to help separate the real science of skincare from the pseudoscience of some skincare brands. Hannah has a degree in Human Biology and many years’ experience working in laboratories around London. Using this experience, Hannah enjoys turning complex science into interesting, engaging and easy to digest pieces to read. In her spare time, Hannah runs, practices yoga and loves cooking plant based foods.

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