What Is Atopic Dermatitis (Eczema)?

Reviewed by: HU Medical Review Board | Last reviewed: May 2023 | Last updated: September 2023

Atopic dermatitis is a long-term (chronic) skin issue. It is the most common type of eczema. The word "atopic" refers to a group of allergy related health issues that often occur together. Seasonal allergies (allergic rhinitis), asthma, and eczema make up this group. "Dermatitis" means inflammation of the skin.1,2

Who gets eczema?

Eczema is often first noticed in childhood. About 10 to 30 percent of kids have eczema. Most of these kids will be diagnosed before the age of 5. Some will outgrow their eczema, but about half will continue to have symptoms into adulthood.3,4

Although it is rare, it is possible for eczema to arise for the first time in adulthood. Overall, as many as 1 in 10 adults have eczema. The severity of symptoms and how often they occur can vary. Eczema is not contagious and cannot be spread from person to person.4,5

What causes eczema?

There are many factors that can lead to developing eczema. Each person will most likely have a mix of several of these. Experts are still looking for potential causes and trying to understand the current theories about what causes eczema.1,3-5

Problems with the skin barrier

The top layer of the skin (skin barrier) has many roles. It protects from germs and allergens. It also helps with water and fat balance to keep your skin strong and hydrated.3

Problems with the skin barrier can stem from gene changes (mutations). An example of a gene linked to eczema is the filaggrin gene (FLG). Other gene issues may affect protein balance that impact skin strength or the ability to let germs pass through.3

Changes in skin bacteria

Your skin has many different types of germs, including bacteria, on it. These usually do not hurt you or cause infection. But people with eczema may have an overgrowth of one germ (bacteria) called Staphylococcus aureus (Staph aureus or S. aureus). These germs can make proteins that damage the skin barrier or lead to inflammation.3

Immune system issues

Certain parts of the immune system may be too active in people with eczema. They may have too many inflammatory proteins (cytokines), or those proteins may be activated at the wrong time. When the immune system is not working properly, the body responds differently to allergens or germs.3

Neurological issues

People with eczema have severe itching. This itching further breaks down the skin barrier and leads to more inflammation. It is possible that an overactive itch response may be a cause. This response is controlled by the brain.3

Environmental triggers

Certain things in the environment may also increase your risk of developing eczema. These include exposure to:3

  • Air pollution
  • Hard water (with calcium)
  • Food allergens
  • Allergens in the home, like dust mites

What are the symptoms of eczema?

Skin inflammation leads to most of the symptoms that come with eczema. Symptoms may include:1,3-5

  • Dry or cracked skin
  • Severe itching
  • Skin color changes (often red or pink patches on lighter skin and brown, gray, or purple bumps on darker skin)
  • Blisters with crusting or oozing
  • Thickened, leathery areas of skin (plaques)
  • Skin swelling
  • Areas of bumpy skin
  • Crusting or discharge around the ears, eyes, or mouth

Skin changes can occur nearly anywhere on the body. In very young kids, they often occur on the face, scalp, and limbs. As people with eczema get older, eczema commonly affects the flexural surfaces of the body. These areas include the back of the knees, the creases of the elbows, the neck, and the wrists.3

How is eczema diagnosed?

There is no single test to diagnose eczema. Doctors take a history of symptoms and look at the affected areas of skin. A family or personal history of atopic conditions like asthma or allergies can be helpful for diagnosis. Where the rash is and how it behaves can also help.1,3,4

Doctors will also try to rule out other similar conditions, such as contact dermatitis (an allergic or irritation reaction) or psoriasis. Extra tests like blood work or skin biopsies are rarely needed. These tests are only used to rule out other issues.1,3,4

Most cases of eczema can be treated by a primary care doctor. A dermatologist (skin doctor) may be needed in severe cases.1,3,4

How is eczema treated?

While there is no cure for eczema, there are ways to manage symptoms. The treatment approach depends on the symptoms and their severity.1,4-7

The first steps in treating eczema are usually lifestyle changes. These changes may include:1,4-7

  • Daily moisturizing
  • Limiting exposure to cold or dry air
  • Using over-the-counter anti-itch creams

If you still have symptoms, you may need to try steroid creams or drugs that suppress the immune system, like oral steroids. There are also newer drugs like dupilumab that target specific steps in the body's inflammatory process. This can help with itch and other symptoms.1,4,7,8

Phototherapy (light therapy) or gradual exposure to allergens (allergy immunotherapy) may also be helpful, too. You and your doctor will work together to create the plan that is best for you.1,4,7,8

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