Doctors don't know exactly what causes eczema. The most common type, atopic dermatitis, resembles an allergy. But the skin irritation is not an allergic reaction.
Causes of Eczema
Eczema is probably caused by a combination of things that may include:
- Genetics. A major risk factor is having relatives who have or had eczema, asthma, or seasonal allergies. A large percentage of children with severe eczema will later develop asthma or other allergies.
- Problems in the way your immune system works
- 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.
- Environment. Children are more likely to get eczema if they are in higher social classes, live in urban areas with higher levels of pollution, or live in colder climates.
- Activities that make your skin more sensitive
- Defects in the skin barrier that allow moisture out and germs in
- Endocrine disorders such as thyroid disease
What Doesn’t Cause Eczema
Eczema is not contagious. You can't catch eczema by coming in contact with someone who has it.
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 doctor to be sure your child's nutritional needs will be met.
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
Infections or allergies
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:
- Cold or flu
- Bacterial infection
- Allergic reaction to something such as mold, pollen, or pet dander
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