What Is Eczema?

Eczema is a common skin condition marked itchy and inflamed patches of skin. It is also known as atopic dermatitis. It is more common in babies and young children. It occurs on the faces of infants, as well as inside the elbows and behind the knees of children, teenagers, and adults. It is caused by an overactive immune system. Up to 20 percent of children and one to three percent of adults develop atopic dermatitis, according to the American Academy of Dermatology. In rare cases, atopic dermatitis can first appear during puberty or adulthood. It affects males and females equally.

When people refer to eczema, they usually mean atopic dermatitis, which is the common and chronic type of eczema. Other types include:

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An eczema flare-up is when one or more eczema symptoms appear on the skin. The cause of eczema is not fully understood.

It is thought to be triggered by an overactive immune system that responds aggressively to the presence of irritants.

Eczema is sometimes caused in part by an abnormal response to proteins that are part of the body. Normally, the immune system ignores proteins that are part of the human body and attacks only the proteins of invaders, such as bacteria or viruses. In eczema, the immune system loses the ability to distinguish between the two, which causes inflammation.

Common triggers of eczema flare-ups include:

Other triggers include stress, food allergies, animal dander, and upper respiratory infections.

Eczema is characterized by itchy, dry, rough, flakey, inflamed, and irritated skin. It can flare up, subside, and then flare up again. It can occur anywhere but usually affects the arm, inner elbow, back of the knee, or head (particularly the cheeks and the scalp). It is not contagious and becomes less severe with age.

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Eczema: Definition, Causes, Treatments & Pictures