Eczema Knowledge Hub

Eczema doesn't have one single cause. Instead, it develops from a combination of genetics, skin barrier weakness, immune changes, and environmental triggers. Here are the five main reasons:

1. Genes — it runs in families. If one parent has eczema, asthma, or allergies, their child has about a 50% chance of developing one of these conditions. If both parents are affected, the likelihood increases to as much as 80%.^[1]

2. Broken skin barrier. Many people with eczema have a weakened skin barrier, often linked to changes in the filaggrin gene. This allows water to escape and lets irritants or allergens enter, which can trigger flare-ups.^[2]

3. Overactive immune system. In eczema, the immune system reacts too strongly, driving inflammation that causes the redness and intense itching seen during flares.^[3]

4. Triggers at home. Everyday things can worsen eczema, including dust mites, pet dander, certain foods, scratchy fabrics, harsh or fragranced detergents, and unsuitable skincare routines.^[3]

5. Environmental triggers. Sudden changes in temperature, humidity, dry air, pollution, pollen, smoke, or sweat can damage the skin barrier and worsen dryness, making flares more likely.^[3]

In short, eczema happens when a vulnerable skin barrier meets an overactive immune system, with genetics and everyday triggers combining to cause flare-ups.