Atopic dermatitis is the most common type of eczema. It begins in childhood with a rash that is itchy, comes and goes, and occurs on both sides of the body equally. Atopic dermatitis causes the skin to become inflamed with redness, swelling, cracking, weeping, crusting, and scaling.
Definition of "Atopic"
"Atopic" and "atopy" are terms that were introduced years ago to describe a group of patients who have a personal or family history of one or more of the following conditions:- hay fever (allergic rhinitis)
- asthma
- atopic dermatitis
Cause of Atopic Dermatitis is Complicated
What causes atopic dermatitis is actually a hotly debated topic. It is believed to be caused by a combination of environmental and genetic factors, but the exact cause is not known. Clearly, atopic dermatitis runs in families, but family members can have it in varying degrees from just a little dry skin in the winter to extensive rashes that require several different treatments to control. Stress can make the symptoms worse, but it does not cause the disease. Atopic dermatitis is not contagious.The Itch-Scratch Cycle
Atopic dermatitis is known as "the itch that rashes." People with atopic dermatitis develop skin itches that cause them to scratch. They seem to be more sensitive to itching and need to scratch longer to get relief. This scratching and rubbing actually irritates the skin more and makes the inflammation worse, which leads to even more itching and scratching. This cycle even continues while the person is asleep. The itching also gets more noticeable at night when people are less busy.Factors Under Study
Even though the exact cause of atopic dermatitis is not known, we are learning more and more about various factors that play a role in this itchy disease. Some of the important concepts being studied are:- Overreaction of the skin to things it comes in contact with
- Abnormalities in the barrier function of the skin -- why the skin is more "leaky"
- Changes in various immune system cells, especially T-cells
- Why atopic skin does not fight infection as well as normal skin
- Changes in the structure of the skin in people who have had atopic dermatitis for a long time
- The over-response of various chemicals in the body that cause inflammation, swelling, and redness
Sources:
Fritsch, Peter, and Norbert Reider. "Other Eczematous Eruptions." Dermatology. Ed. Jean Bolognia. New York: Mosby, 2003: 121-2.
Habif, Thomas. "Eczema and Hand Dermatitis." Clinical Dermatology, 4th Edition. Ed. Thomas Habif, MD. New York: Mosby, 2004. 63.
Leung, Donald, et al. "New insights into atopic dermatitis." The Journal of Clinical Investigation 113(2004): 651-7.
