What causes eczema? Risk factors and triggers, explained

If you suffer from eczema, you know how hard it can be to resist the urge to scratch those unbearably itchy patches on your skin. Sure, scratching can give you short-term relief, but you know it will only make you worse in the long run. Eczema can be difficult to manage and you have probably wondered on more than one occasion: causes eczema? But first, it’s important to understand what eczema is in the first place.

There are different types of eczema, but atopic dermatitis is the most common form, affecting about 10 percent of the US population, according to the National Eczema Society. Eczema is most commonly diagnosed in children, but many adults also suffer from it. In fact, up to one in four people with eczema can be diagnosed in adulthood, and that number appears to be rising, according to a 2019 study published in the Journal of Allergy and Clinical Immunology: In Practice.1

Although it’s quite common to be diagnosed with eczema, getting to the bottom of what causes eczema isn’t as clear cut. Researchers are still working to understand the exact mechanism of the disease; in the meantime, there are plenty of them To do know the possible causes of eczema and what triggers flare-ups. Here, dermatologists break down everything you need to know.

First, what are the most common eczema symptoms?

Before talking about all the possible reasons why you have eczema, it’s good to first recognize the signs and symptoms. Eczema tends to affect folds of skin, including elbows and knees, ankles, wrists, eyelids and the back of the neck. According to the Mayo Clinic, common symptoms of eczema can include:

  • Dry and itchy skin
  • Skin inflammation that may appear red, purple, or brownish
  • Raw, cracked, swollen, or scaly skin
  • Small raised bumps

Although you may experience any or all of these symptoms, it is important to note that eczema can present differently from person to person depending on your skin tone. “Different ethnic populations have different presentations and patterns of eczema,” Azeen Sadeghian, MD, FAAD, board-certified dermatologist in Baton Rouge, Louisiana and member of the American Academy of Dermatology, told SELF. For example, if you have a darker skin tone, your inflammation may take on a purple or purple color (instead of looking pink or red as it usually does with lighter skin tones). And over time, you may also see skin discoloration if your eczema is left untreated.

Additionally, black people sometimes develop eczema on the outside of the forearms or elbows, as opposed to the inner folds of skin, Dr. Sadeghian notes. Follicular accentuation – where the skin around the hair follicles becomes pronounced and bumpy – is also a more common symptom in darker skin types. These important nuances can sometimes present challenges when it comes to diagnosing skin conditions in people of color.

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What causes eczema?

The underlying causes of eczema are complicated, says Dr. Sadeghian. “Our skin cells are normally like a brick wall barrier covered in varnish to protect it,” she says. But when someone has eczema, that metaphorical veneer doesn’t work as it should, leaving the bricks – or in this case, the skin cells – more vulnerable to invasion.

As a result, your skin becomes very sensitive to any irritants, allergens, or environmental factors that might compromise it. And, as Dr. Sadeghian explains, any damage to your skin barrier causes more inflammatory cells to build up in the affected area, creating a chain reaction that manifests as eczema.

Researchers don’t know why some people are more susceptible to eczema than others, but according to the American Academy of Dermatology, the following factors may increase your risk:

family history

Genetics is a determining factor in whether or not you will develop eczema. “If it runs in your family, you’re more likely to get it,” Amy Kassouf, MD, a Cleveland Clinic-affiliated, board-certified dermatologist who practices in Twinsburg, Ohio, tells SELF. A study published in Clinical and experimental allergy which followed 4,089 newborns up to the age of four found that 27% of babies whose parents had eczema developed the disease. Of children who had a parent with eczema, almost 38% were diagnosed, and when both parents had eczema, 50% of children eventually got it.2

Gene mutations

In 2020, a study published in Nature Communication showed that two relatively common variations of a specific gene (the KIF3A gene to be exact) can lead to a weakened skin barrier, which then allows for increased water loss from your skin.3 Researchers have hypothesized that these genetic variations make people who suffer from it more likely to develop eczema, according to the National Institutes of Health.

A protein deficiency

According to the National Eczema Society, more than half of people with eczema may have low levels of a protein called filaggrin. Filaggrin acts as a natural moisturizer that helps your skin ward off pathogens (like a virus, bacteria, or other microorganisms). Going back to the brick wall analogy, people whose bodies don’t make enough filaggrin will be more vulnerable to immune system invaders and less protected by their skin.

Dry skin

Dry skin is one of the main culprits of eczema. “Your skin is supposed to be a barrier against the outside world. But sometimes it starts to break down, either because of its inability to lubricate itself or because you don’t moisturize it enough,” says Dr Kassouf. Some people have skin that is naturally prone to dryness, while others have skin that dries out due to repeated exposure to harsh chemicals or irritants.

Allergies

Allergies no cause eczema, but these two conditions are closely related. Eczema is often found in people who also suffer from hay fever and asthma, Dr. Kassouf says, forming what medical professionals call the “atopic triad.” In this disease progression, known as the atopic march, infants and young children will develop symptoms of eczema, then later progress to asthma and allergic rhinitis. Researchers, who published a study in 2014 in the Journal of Clinical and Cellular Immunologyhypothesized that the weakened skin barrier could be the reason infants with eczema become allergic young adults.4

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