Eczema is a chronic skin condition that weakens your skin’s protective barrier, causing patches of dry, intensely itchy, and inflamed skin. Around 129 million people worldwide have the most common form, atopic dermatitis, and that number has been climbing steadily for decades. Eczema isn’t contagious, and while it often starts in infancy or early childhood, it can appear for the first time at any age.
How the Skin Barrier Breaks Down
Healthy skin works like a brick wall. Skin cells are the bricks, and a protein called filaggrin acts as part of the mortar holding everything together. Filaggrin also keeps the outer layer of skin hydrated, maintains its slightly acidic pH, and helps it resist infection. In many people with eczema, the body doesn’t produce enough filaggrin, or the filaggrin it makes doesn’t function properly.
Without adequate filaggrin, the skin becomes “leaky.” Water escapes more easily from the surface, which dries out the upper layers of skin. That dryness creates a steeper moisture gradient that pulls even more water out, setting up a cycle of worsening dehydration and cracking. At the same time, the weakened barrier lets irritants, allergens, and microbes penetrate deeper into the skin than they normally would.
Once those substances get through, the immune system overreacts. In eczema, the body launches a specific type of inflammatory response (driven by what immunologists call the Th2 pathway) that causes redness, swelling, and itching. This immune overreaction also raises levels of an antibody called IgE, which is the same antibody involved in allergies. That’s why eczema frequently appears alongside asthma and hay fever, a pattern sometimes called the “atopic triad.”
Types of Eczema
Eczema is actually an umbrella term for several related conditions. They share the core features of itching and inflammation but differ in where they appear, what triggers them, and how they look.
Atopic Dermatitis
The most common and most chronic form. It typically shows up on the face, hands, inner elbows, and behind the knees, though it can appear anywhere. Patches of skin become dry, cracked, and intensely itchy. They may ooze or form crusts during flares. Atopic dermatitis tends to run in families and is linked to the genetic and immune factors described above.
Contact Dermatitis
This form develops when your skin touches something that either damages it directly (irritant contact dermatitis) or triggers an allergic reaction (allergic contact dermatitis). Common culprits include soaps, cleaning chemicals, nickel in jewelry, and poison ivy. The rash stays confined to the area that made contact, producing redness, swelling, itching, and sometimes blisters. It clears up once you remove the trigger.
Dyshidrotic Eczema
Characterized by small, fluid-filled blisters that appear suddenly on the sides of the fingers, toes, palms, or soles of the feet. These blisters itch intensely and, over time, the skin may crack, peel, or thicken. Triggers include stress, exposure to metals like nickel or cobalt, seasonal allergies, and excessive moisture on the hands or feet.
Seborrheic Dermatitis
This type targets oily areas of the body: the scalp, the sides of the nose, eyebrows, and upper chest. It produces greasy, inflamed skin covered in white or yellowish flakes. On the scalp, most people know it as dandruff. In infants, it’s called cradle cap. Flares are often triggered by stress, cold weather, or hormonal shifts.
What Eczema Looks Like on Different Skin Tones
Most descriptions of eczema focus on redness, but that’s how it appears on light skin. On darker skin tones, including brown, dark brown, and Black skin, the redness is often hidden. Instead, eczema patches tend to look darker brown, purple, or ashen grey. After a flare heals, darker skin is also more likely to develop areas of lighter or darker pigmentation that can take weeks or months to even out. If you have darker skin and notice persistent itchy patches that don’t look classically “red,” eczema is still a strong possibility.
Common Triggers
Eczema flares are set off by different things in different people, but certain triggers come up repeatedly. Environmental irritants include fragrances, dyes, harsh soaps, rough fabrics like wool, and chemical fumes from sources like wildfires or car exhaust. Airborne allergens like pollen, mold, dust mites, and animal dander are also frequent culprits. Cold, dry air is a classic seasonal trigger, which is why many people with eczema notice their worst flares in winter.
Stress plays a measurable role in triggering flares. Certain foods can worsen eczema in people who have a confirmed food allergy, though food is not a universal trigger. Respiratory viruses, including the flu, can also set off or worsen flares. Identifying your personal triggers is one of the most useful things you can do to manage the condition long-term.
How Eczema Is Diagnosed
There’s no blood test or lab result that confirms eczema. Dermatologists diagnose it based on a combination of what they see on your skin and your medical history. The standard clinical criteria look for four main features: persistent itching, a characteristic rash pattern (flexural areas like inner elbows and behind the knees in adults, face and outer limbs in infants), a chronic or relapsing course, and a personal or family history of eczema, asthma, or hay fever.
Beyond those major signs, doctors look for supporting clues: dry skin, early age of onset, darkening under the eyes, extra skin creases on the palms, and a history of skin infections. The more of these features that are present, the more confident the diagnosis. Patch testing may be added if contact dermatitis is suspected, to identify specific allergens causing a reaction.
Daily Skin Care and the Soak-and-Seal Method
The foundation of eczema management is keeping the skin hydrated and the barrier intact. The most effective approach is called “soak and seal”: you soak in a lukewarm bath to let water absorb into the skin, then immediately apply a thick moisturizer or ointment while the skin is still damp to lock that moisture in. Doing this consistently, at least once or twice daily during flares, can significantly reduce dryness and itching.
Fragrance-free, dye-free moisturizers work best. Ointments and creams are more effective than lotions because they contain more oil and less water. Beyond bathing, avoiding known triggers, wearing soft fabrics against the skin, keeping fingernails short to minimize scratch damage, and using a humidifier in dry environments all help reduce flare frequency.
Treatment Options
When moisturizing alone isn’t enough, topical steroids are the most common next step. These come in a wide range of strengths, from low-potency options like hydrocortisone 1% (available over the counter) up to super-high-potency prescription creams. Your doctor will match the strength to the severity of your flare and the location on your body. Thinner skin areas like the face and eyelids need gentler formulations, while thicker skin on the palms or soles can tolerate stronger ones.
For moderate-to-severe eczema that doesn’t respond to topical treatments, newer therapies have changed the landscape. Injectable biologics work by blocking specific immune signals that drive eczema inflammation. The first and most widely used targets two key inflammatory molecules (IL-4 and IL-13) that are overactive in eczema. Newer options target IL-13 alone or IL-31, which is directly involved in the itch sensation. A separate class of medications, taken as pills or applied as creams, works by blocking enzymes called JAK proteins inside immune cells, dampening the inflammatory cascade from the inside. These treatments have given people with severe, hard-to-control eczema options that didn’t exist a decade ago.
Signs of Infection
Broken, scratched eczema skin is vulnerable to infection, and recognizing the signs early matters. Bacterial infections, most commonly staph, are the most frequent complication. Warning signs include a yellow, crusty texture on or around an eczema patch, oozing bumps or sores, increased pain or burning (as opposed to the usual itch), and new swelling or skin discoloration. If you develop a fever, chills, or nausea alongside worsening skin symptoms, that suggests the infection may be spreading beyond the skin.
Viral infections can also take hold in eczema skin. The most concerning is eczema herpeticum, caused by the herpes simplex virus, which produces clusters of painful, punched-out blisters that spread rapidly. This is a medical emergency that requires prompt antiviral treatment. Any sudden change in the appearance of your eczema, especially painful blisters that look different from your usual flares, warrants urgent evaluation.