The doctor said she had atopic dermatitis. What causes this condition?

 Q. I recently took my daughter to the pediatrician because she had a bad rash. The doctor said she had atopic dermatitis. What causes this condition?

A. Atopic dermatitis (AD) is a type of eczema—chronic inflammation of the skin. It’s quite common, especially in young children. In people with AD, the skin becomes itchy, and dry, and is easily irritated. The condition may persist for years and can damage skin permanently.  No one knows exactly what causes it, but it does run in families. Having a history of other allergic conditions—such as food allergies or hay fever—also increases a person’s chances of developing atopic dermatitis. To help keep your daughter’s problem under control, encourage her not to scratch—which isn’t easy. Scratching and rubbing make the rash itch more. This is referred to as the “itch-scratch cycle.” In some people, temperature extremes—very hot or cold weather—worsen the rash. In others, even simple soaps serve as irritants. Stress or local skin infection may also make it worse.

Your doctor may recommend patch testing to find out which products your daughter should avoid. Allergies to such things as dust mites, animal dander, or pollen can contribute to atopic dermatitis as well. The best treatment is to keep the skin well hydrated. Using topical steroids under the direction of your physician can control inflammation and also reduce the itching that can lead to scratching and infection. After your daughter soaks in a bath, pat her skin dry and apply a heavy layer of moisturizer to seal the water into her skin.