Eczema is a chronic inflammatory skin condition that causes dry, itchy, and irritated patches of skin. It affects roughly 10% to 20% of children and 2% to 10% of adults worldwide, with about 31.6 million people in the United States living with some form of it. The most common type, atopic dermatitis, tends to appear in childhood and can persist or come and go throughout life.
What Happens in the Skin
Healthy skin works like a brick wall: tough, flat skin cells are the bricks, and a mix of natural oils and proteins act as the mortar holding them together. A key protein in this system is filaggrin, which bundles structural fibers inside skin cells and helps them flatten into the compact, waterproof outer layer you can see and touch. As filaggrin breaks down naturally, it also releases molecules that keep skin hydrated.
In eczema, this barrier is compromised. Up to 10% of people carry genetic mutations that reduce or eliminate filaggrin production, and without enough of it, the outer skin layer forms poorly. Water escapes more easily (causing dryness), and irritants, allergens, and microbes slip in more readily. Once these foreign substances penetrate the skin, immune cells overreact, flooding the area with inflammatory signals that cause redness, swelling, and intense itching. This immune response is driven primarily by a branch of the immune system geared toward fighting parasites and responding to allergens, which is why eczema so often overlaps with asthma and hay fever.
How Eczema Looks and Feels
The hallmark of eczema is itch, sometimes so intense it disrupts sleep. The skin becomes dry and cracked, and scratching leads to raw, weeping, or crusted patches. Over time, repeatedly irritated skin can thicken and develop a leathery texture.
On lighter skin, eczema patches typically appear red or pink. On darker skin tones, including brown and Black skin, the redness is often harder to see. Flare-ups tend to look darker brown, purple, or ashen grey instead. Black Americans more commonly develop small bumps on the torso, arms, and legs (papular eczema) or bumps around hair follicles that resemble goosebumps. After a flare clears, darker-skinned individuals are also more likely to see lasting pigment changes where the skin heals lighter or darker than the surrounding area.
In adults, eczema favors the inner elbows, backs of the knees, and the front of the neck. In babies and young children, it more commonly appears on the face, scalp, and the outer surfaces of the arms and legs.
Common Types of Eczema
Atopic dermatitis is the most widespread form and what most people mean when they say “eczema.” It typically starts in early childhood, runs in families, and is closely linked to asthma and allergies. It follows a relapsing pattern: flares that worsen for days or weeks, then periods of improvement.
Contact dermatitis develops when the skin touches something it reacts to. Allergic contact dermatitis is triggered by specific substances your immune system has become sensitized to, like nickel in jewelry, fragrances, or poison ivy. The rash appears only where the substance touched the skin. Irritant contact dermatitis, by contrast, doesn’t involve an immune reaction. It’s caused by direct damage from harsh chemicals, soaps, or prolonged exposure to water.
Other forms include dyshidrotic eczema (small, deep blisters on the palms and soles) and nummular eczema (coin-shaped patches that can appear anywhere on the body).
What Triggers Flares
Eczema flares rarely happen at random. About 80% of adults with the condition are sensitized to specific airborne or food allergens, and identifying personal triggers is one of the most useful things you can do to manage it.
Common triggers include house dust mites, pet dander, pollen, mold, wool clothing, synthetic fragrances, and harsh soaps or detergents. Stress is another major factor. Conflicts at work, in relationships, or within the family can worsen symptoms noticeably. Environmental conditions matter too: dry winter air strips moisture from the skin, while sweating in heat can irritate it.
Indoor air quality plays a larger role than many people realize. Volatile organic compounds released by new furniture, fresh paint, and building materials can aggravate eczema, especially in combination with dust mite allergens. Children growing up near busy roads show higher rates of atopic diseases, likely due to particulate matter and nitrogen dioxide exposure. Tobacco smoke indoors is one of the most significant allergenic irritants in the home environment.
Climate change is also shifting the picture. Rising ozone levels increase the allergen content of pollen, and invasive plants like ragweed are extending allergy seasons into the fall for many sensitized individuals.
How Eczema Is Diagnosed
There is no single blood test or skin biopsy that confirms eczema. Doctors diagnose it based on a combination of what the skin looks like, where the rash appears, and your personal and family history. The most widely used framework requires at least three of four major features: persistent itching, a rash in typical locations (inner elbows, behind knees, face in children), a chronic or relapsing pattern, and a personal or family history of eczema, asthma, or allergies.
Supporting signs include very dry skin, darkening around the eyes, extra lines on the palms, and small bumps around hair follicles on the upper arms and thighs. Doctors also consider whether known triggers like certain foods, wool, stress, or sweating make the condition worse.
Daily Skin Care
The foundation of eczema management is repairing and protecting the skin barrier every day, not just during flares. The most effective daily routine is a method called “soak and seal.” You soak in a warm (not hot) bath for 15 to 20 minutes, pat the skin dry gently without rubbing, and then apply moisturizer or prescribed medication within three minutes, while tiny water droplets are still on the skin. This traps moisture in the outer skin layer and helps compensate for the barrier defects that drive the condition. During flares, you can do this twice daily.
Fragrance-free, thick creams and ointments work better than lotions, which contain more water and evaporate quickly. Avoiding known irritants like scented laundry detergent, fabric softener, and wool clothing is equally important as moisturizing.
Medical Treatment Options
When moisturizing alone isn’t enough, doctors typically start with prescription anti-inflammatory creams. These range from mild formulations safe for the face and skin folds to stronger versions reserved for thick, stubborn patches on the body. Applying them once daily is just as effective as twice daily, and using a mild version twice a week on areas that tend to flare can help prevent new breakouts between episodes.
Non-steroidal prescription creams that calm the immune response locally are another option, particularly for sensitive areas like the face and eyelids where stronger creams aren’t appropriate.
For moderate to severe eczema that doesn’t respond to topical treatments, injectable medications that target the specific immune signals driving the inflammation have changed the landscape. In major clinical trials, about 36% to 38% of patients with moderate-to-severe disease achieved clear or almost clear skin with biologic injections given every other week. These medications work by blocking the immune messengers most responsible for the itch and inflammation cycle.
Infections to Watch For
Broken, scratched skin is an open door for bacteria and viruses. The most common complication is bacterial infection, usually from staph bacteria that live on the skin’s surface. Signs include increased redness, warmth, oozing, and a honey-colored crust forming over patches.
A more serious complication called eczema herpeticum occurs when the herpes simplex virus (the same virus behind cold sores) spreads across eczema-damaged skin. It causes a sudden eruption of small, uniform blisters and “punched-out” sores, often accompanied by fever, swollen lymph nodes, and feeling generally unwell. This is a medical emergency that requires prompt treatment, because it can spread rapidly across large areas of compromised skin.