Pityriasis alba
The skin is the largest organ of the body. The skin and its derivatives (hair, nails, sweat and oil glands) make up the integumentary system. One of the main functions of the skin is protection. It protects the body from external factors such as bacteria, chemicals, and temperature. The skin contains secretions that can kill bacteria and the pigment melanin provides a chemical pigment defense against ultraviolet light that can damage skin cells. Another important function of the skin is body temperature regulation. When the skin is exposed to a cold temperature, the blood vessels in the dermis constrict. This allows the blood which is warm, to bypass the skin. The skin then becomes the temperature of the cold it is exposed to. Body heat is conserved since the blood vessels are not diverting heat to the skin anymore. Among its many functions the skin is an incredible organ always protecting the body from external agents.
Definition
Pityriasis alba is a common skin disorder similar to very mild eczema.
Causes, incidence, and risk factors
The cause is unknown. The disorder is most common in children and adolescents -- particularly in children with dark skin.
Symptoms
Round or oval, colorless patches of skin appear on the face, upper arms, neck, and upper middle of the body. There may be flaky skin, called scales.
The patches don't tan, but may get red quickly in the sun.
Treatment
Symptoms are treated with moisturizers and mild topical steroid creams. The patches usually clear up, but may return.
See also:
-
Disease
Atopic eczema
Eczema is a skin disorder that involves scaly and itchy rashes. Atopic eczema is the most common type. See also:
- Review date:
- April 10, 2009
- Reviewed by:
- Kevin Berman, MD, PhD, Atlanta Center for Dermatologic Disease, Atlanta, GA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
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