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Eczema Causes

Medically Reviewed by Stephanie S. Gardner, MD on August 31, 2026

Doctors don’t know exactly what causes eczema. The most common type, atopic dermatitis, may look and feel like an allergy. But it’s not an allergic reaction.

Eczema is probably caused by a combination of things that may include:

Genetics. A major risk factor is having family who have or had eczema, asthma, or seasonal allergies. A large percentage of children with severe eczema will later develop asthma or other allergies.

Environment. Children are more likely to get eczema if they live in urban areas with higher levels of pollution or live in colder climates. 

Other things that may influence developing eczema include:

  • 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
  • Problems in the way your immune system works

Eczema isn’t contagious. You can’t “catch” eczema by coming in contact with someone who has it.

Eczema isn’t an allergic reaction, either. 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 kids with eczema — cause it or make it worse. 

Before removing particular foods from your child’s diet, talk with your doctor to be sure their nutritional needs are met.

A trigger isn’t something that causes eczema. But it can cause it to flare or make a flare worse.

Skin irritants

The most common triggers are substances that irritate your 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 your skin include:

  • Soaps and cleansers
  • Perfume
  • Makeup
  • Dust and sand
  • Chlorine
  • Solvents
  • 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, flu, or COVID
  • Bacterial infection
  • Allergic reaction to something such as mold, pollen, or pet dander

Stress has also been identified as a possible trigger.

Your environment

Actions and environments that cause your 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

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