Eczema develops when the immune system reacts to triggers inside or outside the body. This overreaction leads to inflammation, causing symptoms like itchy, dry, and irritated skin.

In the United States, eczema affects more than 31 million people of all ages. If you’re living with eczema, you know how much it can affect your skin and everyday life. This article will explain what eczema is, who gets it, what causes it, and how doctors diagnose and treat it.

What Are the Types of Eczema?

There are many subtypes of eczema. The most common subtype, atopic dermatitis, has no clear cause. Other forms include:

• Irritant contact dermatitis
• Allergic contact dermatitis
• Dyshidrotic eczema
• Seborrheic dermatitis

Read more about the types of eczema.

How Is Eczema Diagnosed?

Doctors usually diagnose eczema by asking about your health and family history and doing a physical exam to check for common symptoms, such as dry, itchy, or discolored skin. In some cases, they might do a skin patch test or other procedures to confirm the diagnosis.

Learn more about how eczema is diagnosed.

What Causes Eczema?

Researchers don’t yet know why some people get eczema, but they’ve learned a lot about this skin condition. Many researchers believe that people who develop eczema have genetic mutations (variants, or changes) that cause problems with their skin’s barrier. When the skin's protective barrier is damaged, it loses water, causing dryness. This weakened barrier lets irritants get into the skin more easily, which can activate the immune system and cause inflammation​​​.

People with eczema also have differences in the way their immune systems react. For example, contact dermatitis happens when the immune system overreacts to harmless substances such as soaps, detergents, jewelry, and other everyday items. These substances can cause eczema or lead to flares later on. Eczema is often found in people who also have asthma or food allergies, which are linked to immune system issues.

Common triggers for eczema flare-ups include:

• Skin dryness
• Soaps
• Detergents
• Cleaning products
• Metals, such as nickel
• Contact with certain foods
• Cigarette smoke
• Wool, polyester, or other fabrics
• Emotional stress
• Sweat

Eczema is not contagious. This skin condition isn’t spread by infection, and someone who has eczema can’t pass it to another person.

Many children outgrow eczema. In about 80 percent of children with eczema, symptoms go away within about 10 years. Eczema can also appear in later adulthood, often affecting different parts of the body than pediatric eczema does.

Read more about the causes and risk factors for eczema.

What Are the Symptoms of Eczema?

Eczema symptoms often cause significant discomfort. Dryness and itching can lead to scratching that can hurt and damage the skin, causing:

• Swelling — This refers to puffiness or inflammation in the skin caused by fluid build-up in response to irritation or infection.
• Thickening — Ongoing scratching or rubbing can cause the skin to become tough and leathery, a condition called lichenification.
• Scales — Flaky patches of dry, dead skin can peel off, often resulting from persistent inflammation or dryness.
• Cracks — Painful splits in the skin can occur when dry, irritated skin loses elasticity, leaving it vulnerable to tears.
• Crusting — Scablike formations can develop when fluid from weepy eczema patches dries and hardens, sometimes indicating infection.
• Pustules — Small, pus-filled bumps can form when eczema becomes infected with bacteria.

In some cases, eczema can lead to skin infections.

Eczema can also cause problems beyond the skin. For example, the constant itchiness can make it hard to sleep, leading to insomnia. People with eczema may be at higher risk of mental health issues such as depression or anxiety, especially if their visible rashes cause emotional stress or they worry that others think eczema is contagious.

Eczema itself isn’t life-threatening. However, rare complications can occur from severe forms such as eczema herpeticum, which is caused by the common herpes virus. This condition can cause serious symptoms, including bacterial superinfections, dangerously low blood pressure, and — in rare cases — death. Eczema also increases the risk of cellulitis, a deeper skin infection caused by bacteria.

Read more about the symptoms of eczema.

How Was Eczema Discovered?

The history of eczema goes back thousands of years. In the fifth century B.C.E., the Greek physician Hippocrates described a person with chronic (long-lasting) itching, which might have been eczema. The word “eczema” comes from a Greek term meaning “eruption” or “boiling over.”

In the mid-1800s, Viennese dermatologist Ferdinand von Hebra published one of the most detailed descriptions of eczema at the time. He described a rash — which he called prurigo — that started in infancy, recurred (came and went over time), and caused intense itching, crusting, and papules (small bumps). For the next several decades, doctors debated how to classify the different types of eczema-related diseases and whether they came from external triggers or internal biological problems.

The 1950s brought a breakthrough with the introduction of corticosteroids, some of the first effective eczema treatments. Topical steroids, which are applied to the skin, are still the mainstay of eczema management, although treatment options have expanded in recent decades to include more types of topical and systemic (bodywide) treatments.

How Is Eczema Treated?

Eczema can be tricky to manage. You might need to try multiple approaches before finding one that works best for you. For mild eczema, moisturizers, skin barrier repair creams, over-the-counter allergy medications, and lifestyle changes such as reducing stress or avoiding triggers may help. To help manage moderate symptoms, doctors may prescribe topical corticosteroids or immunosuppressants to calm the immune system in affected areas. More severe eczema may call for systemic medications. Treatment may also depend on the type of eczema you have.

Learn more about eczema treatments.

How Does Eczema Differ From Psoriasis?

Eczema and psoriasis are two different skin conditions, although they share some symptoms and treatments. Both involve issues with the immune system, but they’re caused by different immune responses. Eczema is more common in babies and young children, whereas psoriasis often starts in adulthood. Unlike psoriasis, eczema usually appears as thinner, less defined, discolored patches of skin.

Meet Your Team

On MyEczemaTeam, the social network for people with eczema and their loved ones, more than 54,000 members come together to ask questions, give advice, and share their stories with others who understand life with eczema.

Have you been diagnosed with eczema? How does it feel like to you, and how do you manage your symptoms? Share your experience in the comments below, start a conversation by posting on your Activities page, or connect with like-minded members in Groups.