Eczema is a group of conditions that cause inflamed, itchy, and irritated skin. It affects roughly 10% of people worldwide, making it one of the most common skin conditions at any age. The most frequent form, atopic dermatitis, typically begins in childhood but can persist into adulthood or appear for the first time in adults.
What Happens in the Skin
Healthy skin works as a barrier, locking moisture in and keeping irritants and allergens out. In eczema, that barrier breaks down. A key player is a protein called filaggrin, which helps skin cells flatten and pack tightly together to form the outermost protective layer. When genes that produce filaggrin are faulty, the skin can’t build a proper barrier. Water escapes more easily (causing dryness), and allergens slip through more readily (triggering inflammation).
Once allergens penetrate the weakened barrier, the immune system overreacts. Immune cells flood the area and release signaling molecules that drive itching, redness, and swelling. One of these signals directly activates nerve endings in the skin, creating intense itch. Scratching damages the skin further, lets in more irritants, and triggers more inflammation. This itch-scratch cycle is what makes eczema so persistent and frustrating.
The immune overreaction also suppresses filaggrin production even more, making the barrier problem worse. So eczema feeds itself: a leaky barrier invites immune activation, and immune activation weakens the barrier further.
What Eczema Looks and Feels Like
The hallmark symptom is itch, sometimes severe enough to disrupt sleep. The skin is typically dry, and during flares it becomes inflamed and may crack, weep, or develop small blisters. Over time, repeatedly scratching the same areas can thicken and toughen the skin, a change called lichenification.
Where eczema shows up depends on age. In babies and young children, it tends to appear on the face, scalp, and outer surfaces of the arms and legs. In older children and adults, it favors the inner elbows, backs of the knees, neck, and hands. The groin and armpits are usually spared.
On lighter skin, eczema patches typically look red and inflamed. On darker skin tones, the redness can be harder to spot. Instead, affected areas may appear dark brown, purple, or ashen gray. This difference matters because eczema in people of color is frequently underdiagnosed or misidentified, partly because most reference images online show the condition only on light skin.
The Six Types of Eczema
Eczema isn’t a single disease. Six main types fall under the umbrella, each with distinct triggers and patterns:
- Atopic dermatitis: The most common form, strongly linked to genetics and family history of allergies or asthma. It’s chronic and relapsing.
- Contact dermatitis: Caused by direct contact with an irritant (like harsh soap) or an allergen (like nickel). It often produces a burning sensation along with itch.
- Dyshidrotic eczema: Causes small, intensely itchy blisters on the palms, fingers, and soles of the feet.
- Nummular eczema: Produces coin-shaped patches of irritated skin, often triggered by dry skin or minor injuries.
- Neurodermatitis: Starts with an itchy patch that becomes thicker and more irritated with repeated scratching.
- Seborrheic dermatitis: Affects oily areas like the scalp, face, and chest, causing flaky, scaly patches.
Common Triggers for Flares
Eczema tends to come and go. Understanding what sets off a flare helps you reduce the frequency and severity of episodes. About 80% of adults with eczema are sensitized to specific airborne or food allergens, meaning their immune system reacts to substances that wouldn’t bother most people.
Environmental triggers include dry or cold weather (children tend to flare in fall and winter), heat and poor nighttime air cooling, air pollution from traffic, volatile organic compounds released by new furniture or building materials, and tobacco smoke, which is one of the strongest indoor triggers. Pollen can worsen eczema too, particularly on the head and neck during high-pollen seasons.
Stress is another well-documented trigger. Conflicts at work, in relationships, or at home can set off or intensify symptoms. Other common triggers include harsh soaps, fragrances, rough fabrics like wool, sweat, and sudden temperature changes.
How Eczema Is Diagnosed
There’s no single blood test or biopsy that confirms eczema. Doctors diagnose it based on your history and a physical exam. The standard criteria require three things to be present: persistent itch, visible eczema in a typical pattern for your age, and a chronic or relapsing course. A personal or family history of allergies, asthma, or hay fever strengthens the diagnosis, as does very dry skin.
Doctors also need to rule out other conditions that can look similar, such as psoriasis, fungal infections, or scabies. If there’s any uncertainty, a dermatologist can help distinguish between these based on the specific appearance and distribution of the rash.
Treating Mild to Moderate Eczema
Treatment follows a step-by-step approach, starting with the simplest measures and escalating only if needed. The foundation is daily moisturizing. Thick, fragrance-free creams or ointments applied right after bathing help repair the skin barrier and reduce water loss. This alone can significantly cut down on flares.
When a flare does happen, prescription anti-inflammatory creams are the first line of defense. Topical corticosteroids come in a range of strengths and are applied directly to inflamed skin for short periods to calm the immune reaction. For sensitive areas like the face or skin folds, non-steroidal options that calm inflammation through a different pathway are available and safe for longer-term use. Newer topical options work by blocking specific enzymes involved in inflammation.
Wet wrap therapy, where damp bandages are layered over moisturized skin, can help during severe flares by increasing moisture absorption and reducing itch.
Options for Severe Eczema
When topical treatments aren’t enough, newer systemic therapies have transformed care for people with moderate to severe eczema. Biologic medications are injectable drugs that target specific immune signals driving the disease. Some block the pathways responsible for inflammation and barrier damage, while others target the signal that directly causes itch. These treatments have shown strong results in reducing both visible symptoms and the relentless itching that defines severe eczema.
Another class of newer medications comes in pill form and works by interrupting the signaling chains inside immune cells that sustain inflammation. These tend to work quickly, with some patients noticing improvement within the first few weeks. Both types of systemic therapy represent a major shift from older approaches that broadly suppressed the immune system and carried heavier side effects.
Infection Risks to Watch For
Broken, scratched skin is vulnerable to infection, and people with eczema face higher risks than average. The most common bacterial culprit is Staphylococcus aureus, which colonizes eczema-affected skin at high rates. Signs of bacterial infection include increased redness, warmth, oozing, crusting (especially honey-colored crusts), and worsening pain rather than just itch.
A more serious complication is eczema herpeticum, where the herpes simplex virus (the same virus that causes cold sores) spreads rapidly across eczema-damaged skin. It produces clusters of small, punched-out blisters that can be painful and may come with fever and fatigue. Eczema herpeticum requires prompt treatment because it can spread quickly and become dangerous, particularly in young children. Research has found that people who develop this complication tend to carry strains of Staph bacteria that produce particularly potent toxins, suggesting the bacterial environment on the skin may play a role in vulnerability to viral complications.
If your eczema suddenly changes character, spreads rapidly, becomes painful rather than just itchy, or you develop a fever alongside a flare, those are signs that infection may be involved and prompt evaluation is important.