Eczema is a group of conditions that make the skin inflamed, itchy, and often dry or cracked. The word itself comes from the Greek “ekzein,” meaning “to boil over,” which describes how the skin can look red and blistered during a flare. It affects roughly 10% of people worldwide, and while it often starts in childhood, it can appear at any age. The most common form, atopic dermatitis, is what most people mean when they say “eczema.”
What Happens Inside the Skin
Healthy skin works as a tight barrier, keeping moisture in and irritants out. In eczema, that barrier has gaps. A key factor is a protein called filaggrin, which helps skin cells hold their shape and retain water. When filaggrin is deficient, the outer layer of skin becomes structurally disorganized. The layers of protective fats that normally seal the skin together develop gaps and irregularities, allowing allergens, bacteria, and chemical irritants to slip through into deeper layers where they trigger inflammation.
This isn’t just dry skin. The immune system overreacts to substances that wouldn’t bother intact skin, creating a cycle: the barrier lets irritants in, the immune system fires up, inflammation damages the barrier further, and the cycle repeats. That immune overreaction is why eczema often runs alongside other allergic conditions like asthma and hay fever.
Types of Eczema
Eczema isn’t a single disease. The major types differ in what triggers them and where they show up.
- Atopic dermatitis is the most common type, typically starting in infancy or early childhood. It’s driven by genetics and immune system dysfunction, and it tends to affect the creases of elbows, behind the knees, and the face.
- Contact dermatitis happens when the skin touches a specific irritant or allergen. Anyone can develop it. Common culprits include nickel, fragrances, preservatives in cosmetics, hair dye chemicals, soaps, and detergents.
- Seborrheic dermatitis targets areas with more oil glands, like the scalp (where it causes dandruff), the sides of the nose, and the eyebrows.
- Dyshidrotic eczema produces small, intensely itchy blisters on the palms, fingers, and soles of the feet.
What Eczema Looks and Feels Like
The hallmark symptom is itch, often intense enough to disrupt sleep. In the early or acute stage, eczema appears as red, inflamed patches with small raised bumps. The skin may weep or ooze clear fluid, and scratching creates visible raw spots.
When eczema persists over weeks or months, the skin changes. Repeated scratching and rubbing cause the skin to thicken and develop exaggerated lines, a process called lichenification. The patches may look leathery, darker or lighter than surrounding skin, and feel rough to the touch. In people with darker skin tones, eczema often appears brown, purple, or grayish rather than the classic pink-red seen in lighter skin, which can sometimes delay recognition.
Common Triggers
Eczema flares don’t come from nowhere. They’re typically set off by specific triggers, though the list varies from person to person. The most well-documented categories include:
Skin irritants are the broadest trigger. Excessive washing, harsh soaps, and detergents strip what little protective barrier the skin has. Fragrances (in perfumes, lotions, and household products) are among the most commonly identified allergens in cosmetic-related reactions. Preservatives like formaldehyde-releasing compounds and isothiazolinones also provoke flares in sensitive individuals.
Air quality matters more than most people realize. Studies have linked eczema flares to particulate matter, nitrogen oxides, and carbon monoxide in outdoor air. Indoors, volatile organic compounds from paints, furniture, and cleaning products contribute. Exposure to tobacco smoke during pregnancy is associated with eczema development in children after birth.
Food triggers play a role for some people, especially children. The five foods most clearly linked to eczema flares are eggs, milk, soy, peanuts, and wheat. These don’t cause eczema in everyone, but in those who are sensitized, they can worsen symptoms significantly.
Metals like nickel, cobalt, and chromium (found in jewelry, zippers, and some electronics) are classic contact triggers. Heavy metals like cadmium and lead have also been linked to allergic responses in recent research.
The Connection to Asthma and Allergies
Eczema often doesn’t travel alone. There’s a well-documented pattern called the atopic march: eczema appears first in infancy, followed by food allergies, then asthma, and later hay fever. Not every child with eczema progresses through all stages, but the risk is real. One study found that about 28% of people with atopic dermatitis also had asthma.
The risk of developing asthma is highest in children whose eczema started very early, was severe and persistent, or was accompanied by early sensitization to foods or inhaled allergens. A family history of allergic conditions also raises the likelihood. This connection is one reason dermatologists take childhood eczema seriously, even mild cases.
How Eczema Is Diagnosed
There’s no blood test or biopsy that confirms eczema. Diagnosis is entirely clinical, based on what the skin looks like, where the patches appear, and your personal and family history. Dermatologists use a set of criteria first established in 1980 and refined several times since, looking for a combination of features: chronic or relapsing itchy skin, typical distribution patterns (flexural creases in adults, face and outer limbs in infants), personal or family history of atopic conditions, and early age of onset.
A simplified version of these criteria allows non-specialists to make the diagnosis without lab work. The key mandatory feature is itchy skin (or a parent reporting scratching in a young child), plus several supporting features from the list above.
Treatment Options
Most people with eczema manage it effectively with topical treatments applied directly to the skin. The foundation is simple: consistent moisturizing to reinforce the skin barrier. On top of that, topical corticosteroids remain the first-line treatment for flares, reducing inflammation and itch quickly. For sensitive areas like the face or skin folds, calcineurin inhibitors offer a steroid-free alternative.
Newer topical options have expanded the toolkit. Creams that block specific inflammatory pathways (PDE-4 inhibitors and topical JAK inhibitors) are now recommended in clinical guidelines. The American Academy of Dermatology’s 2025 update added two new topical therapies to its recommendations, giving patients more choices when steroids aren’t ideal.
For moderate to severe eczema that doesn’t respond to creams alone, the treatment landscape has changed dramatically in recent years. Injectable biologics that target specific immune signals have become a mainstay. These work by dialing down the overactive immune pathways responsible for inflammation, and they’ve been effective for many people who previously cycled through treatments without relief. Oral medications that block a family of immune signaling enzymes (JAK inhibitors) offer another systemic option, with three now approved. Current guidelines specifically recommend against long-term use of oral steroids for eczema, given their side effect profile.
What treatment looks like in practice depends on severity. Someone with mild eczema may only need a good moisturizer and occasional steroid cream during flares. Someone with widespread, persistent disease might use a biologic injection every few weeks alongside daily skin care. The goal in all cases is the same: break the itch-scratch cycle, calm inflammation, and restore the skin barrier enough to prevent the next flare.