What Causes Eczema (Atopic Dermatitis)?

Reasons for flare-ups in children and adults

Researchers are working to figure out what causes eczema (atopic dermatitis). Because eczema runs in families, genetics are likely involved. Other factors, including your exposure to allergens or irritants such as pollution and cigarette smoke, likely also play a role.

This article will discuss common genetic and environmental factors that may cause eczema in babies and adults.

Atopic Dermatitis Irritants

Verywell / Katie Kerpel

Common Causes

About 1 in 10 Americans have atopic dermatitis, and millions worldwide live with the condition. Atopic dermatitis is a form of eczema, a group of conditions that cause inflamed skin. Anyone, from newborns to people older than 65, can have atopic dermatitis.

If you have atopic dermatitis, you may experience dry, itchy skin that develops into a rash with scratching. Rashes can be quite painful and may increase your risk of developing a skin infection.

In Babies

Atopic dermatitis is common in children. Symptoms typically show up during the first months of a baby’s life. People of all ages can be susceptible to allergens (substances that trigger an allergic reaction). But babies may be more vulnerable to irritants because their skin is so sensitive. 

Keep in mind that the severity of childhood eczema varies widely. And not all babies or children have the same symptoms or rash patterns. It’s possible for eczema to go away during childhood and return in adulthood.

Irritants for Babies

Potential irritants that a baby may be exposed to include:

  • Fragrances
  • Soaps
  • Fabrics 
  • Baby wipes that contain isothiazolinone
  • Certain shampoos and lotions containing cocamidopropyl betaine 
  • Cigarette smoke, if an adult in the household smokes

In Adults 

Atopic dermatitis can be a lifelong condition. A 2019 study found that 7.3% of American adults had the condition. Although people over the age of 65 can develop atopic dermatitis, it's rare.

Asian and Black people are more likely to develop atopic dermatitis. You're also more likely to develop atopic dermatitis if a relative has it or a related condition such as food allergies, asthma, or hay fever.

If your genes make you susceptible to developing atopic dermatitis, other factors such as the climate may contribute to symptoms and flare-ups.

People at risk of developing atopic dermatitis are more likely to get it if they live in a city, a place that's damp and cold for part of the year, or a mountainous region with low temps for part of the year. On the flip side, living in a rural, warm, and/or humid area may decrease your risk of developing atopic dermatitis.

Irritants that affect babies can also affect adults. However, adults may be more likely to come into contact with the following common irritants:

  • Metals, particularly nickel (which is common in people who wear jewelry)
  • Some antibacterial ointments, including those containing neomycin
  • Formaldehyde in disinfectants, glues, and adhesives
  • Paraphenylenediamine, which can be found in temporary tattoos and leather dyes 

Stress is another trigger that is more common in adults. However, researchers don’t really know why stress exacerbates symptoms.

Differences in Rash Appearance by Age

The appearance of atopic dermatitis may depend on your age. In fact, one of the biggest differences between childhood and adult eczema is how it looks on the skin:

  • Infants tend to have rashes on the scalp and face, particularly on the cheeks, chin, scalp, and forehead. Skin usually looks weepy and red.
  • Babies between 6 months and 12 months often develop eczema on their knees and elbows because of irritation from crawling.
  • Toddlers also experience irritation around the knees and elbows but may develop a rash on their ankles, hands, and wrists. A rash around the eyes and mouth is also common in kids under 5. The rash is also more likely to appear scaly.
  • Children over 5 typically have rashes behind the knees and in the folds of the elbows. At this age, some people have rashes only on their hands.
  • In adults, rashes may appear in these areas but are more common on the hands and eyelids. People who have had lifelong eczema may have thick patches of skin that are darker or lighter than other areas.

Types of Eczema

Eczema is an umbrella term used to describe symptoms that cause itching and inflammation. Atopic dermatitis is the most common type of eczema. 

Other types of eczema include:

  • Contact dermatitis: This occurs when an irritant that physically touches your skin causes a reaction.
  • Dyshidrotic eczema: This type of eczema produces many small blisters on the hands and feet. Another name for it is pompholyx. It can be acute or chronic.
  • Seborrheic eczema: This chronic form of eczema happens primarily in areas of the body with many oil-producing sebaceous glands, such as the nose and scalp.
  • Stasis dermatitis: This type of eczema happens in people with poor blood flow, usually in the lower legs.
  • Neurodermatitis: Also called lichen simplex chronicus, this type of eczema produces an itchy patch that gets itchier because of scratching. The itching can be so intense that it can interfere with daily activities like sleep.
  • Nummular eczema: Unlike other types of eczema, the nummular form produces round, itchy patches. Because it looks a lot like a fungal skin infection, it’s a good idea to see a dermatologist to confirm the diagnosis.


The skin acts as a barrier against allergens, microbes, dust mites, and other foreign objects. It also helps prevent water loss. A gene called FLG helps to create a strong barrier in the outermost layer of the skin. Having a mutation in FLG is a major risk factor for atopic dermatitis.

Other mutations that may increase the risk of atopic dermatitis are involved in the immune system. These mutations may lead to a very sensitive immune system. The immune system may overreact to everyday things like pollen and dust.

Mutations associated with atopic dermatitis are found in genes that increase immunoglobin E (IgE) production. IgE are antibodies the immune system produces to mount an allergic response.


Atopic dermatitis is usually diagnosed based on the person's history and physical examination features. In atypical cases, a skin biopsy is occasionally used to rule out malignancy or other diagnoses.

Lifestyle Risk Factors

Some people are more susceptible to developing eczema because of lifestyle risk factors. These include:

  • Jobs or hobbies that involve chemical irritants: A workplace or activity that exposes you to chemicals for long periods of time can make eczema worse. For example, if you work in a spa and handle chemicals all day long, this may increase your risk of developing eczema or make existing symptoms worse.
  • Hobbies or jobs that involve manual labor: Using your hands a lot, without wearing gloves, can irritate the skin. For example, not wearing gloves while gardening can cause you to develop eczema on your hands.
  • Excessive handwashing, showering, or bathing: Washing your skin is important for maintaining day-to-day hygiene. However, overwashing can dry out the skin and negatively impact its moisture barrier.
  • Frequent scratching or rubbing of the skin: Physical irritation can also increase the likelihood that you’ll develop eczema. This includes wearing itchy clothing or garments that are too tight. 

Treatment for Eczema

There is no cure for it, but eczema can be managed. Taking care of your skin by bathing with gentle, fragrance-free cleansers and using a moisturizer can help relieve symptoms. Fortunately, rashes can be prevented in many ways, and many medications can help.


Atopic dermatitis (eczema) is an itchy skin rash due to an immune reaction. The reaction can be triggered by many different kinds of irritants in babies and adults. Certain genetic mutations can increase the risk of atopic dermatitis, as can environmental factors.

A Word From Verywell

Having a child with eczema or living with eczema yourself can be challenging. While it can be manageable, for many it’s still a lifelong condition that causes discomfort and pain. It can also cause issues with self-esteem.

However, there are ways to cope with the emotional impact of eczema, including support groups, stress reduction techniques, and reducing the symptoms.

Frequently Asked Questions 

What causes sudden eczema flare-ups?

A sudden flare-up can happen because you were exposed to a trigger such as a pollutant or irritant. It can also happen if you experience a period of heightened stress. Flares can also occur spontaneously without exposure to any known trigger.

Do certain foods make eczema worse?

There’s a link between food allergies and eczema. People with eczema are more likely to have food allergies and vice versa. However, foods that directly cause flare-ups are rare. Some people may experience flare-ups after eating certain foods, but this is rare and most people with atopic dermatitis do not require specific food avoidance.

What does the immune system have to do with eczema?

People with eczema probably have over-reactive immune systems. This causes the immune system to produce an inflammatory response when exposed to certain triggers. It doesn't mean you have a weak immune system, but that it’s highly responsive, which can sometimes be problematic.

19 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Steph Coelho
Steph Coelho is a freelance health writer, web producer, and editor based in Montreal. She specializes in covering general wellness and chronic illness.