Doctors don't know exactly what causes eczema. The most common type of eczema -- atopic dermatitis -- resembles an allergy. But the skin irritation, which is more often seen in children rather than adults, is not an allergic reaction.
The current thinking is that eczema is caused by a combination of factors that include:
- Abnormal function of the immune system
- Activities that may cause skin to be more sensitive
- Defects in the skin barrier that allow moisture out and germs in
- Endocrine disorders such as thyroid disease
What We Know About the Causes of Eczema
Here's more detail on what's known about eczema causes:
Eczema is not contagious. You or your children can't catch eczema by coming in contact with someone who has it.
Eczema runs in families. That suggests a genetic role in eczema's development. A major risk factor is having relatives who have or had:
Mother's age at time of birth. It's not clear why, but children born to older women are more likely to develop eczema than children born to younger women.
Role of environment. Children are more likely to develop eczema if they:
- Are in higher social classes
- Live in urban areas with higher levels of pollution
- Live in colder climates
Eczema is not an allergic reaction. Even so, a large number of children who have eczema also have food allergies. That doesn't mean that certain foods such as dairy, eggs, and nuts -- common food allergy triggers in children with eczema -- cause it or make it worse. Before removing particular foods from your child's diet, talk with your health care provider to be sure your child's nutritional needs will be met.
The Role of Triggers in Eczema
A trigger is not something that causes eczema. But it can cause it to flare or make a flare worse.
The most common triggers are substances that irritate the skin. For instance, in many people with eczema, wool or man-made fibers that come in contact with the skin can trigger a flare.
Examples of other things that can irritate the skin include:
- Soaps and cleansers
- Dust and sand
- Irritants in the environment
- Cigarette smoke
Flares can also be triggered by certain conditions that have an effect on the immune system. For instance, things that can trigger or worsen a flare include:
Stress has also been identified as a possible trigger.
Actions and environments that cause the skin to dry out or become otherwise sensitive can trigger flares. Some examples include:
- Prolonged exposure to water
- Being too hot or too cold
- Sweating and then becoming chilled
- Taking baths or showers that are too hot or last too long
- Not using a skin lubricant after a bath
- Low humidity in the winter
- Living in a climate that is dry year-round