Questions and Answers about Psoriasis
What Is Psoriasis?
Psoriasis is a chronic (long-lasting) skin disease of
scaling and inflammation that affects 2 to 2.6 percent of the United
States population, or between 5.8 and 7.5 million people. Although the
disease occurs in all age groups, it primarily affects adults. It
appears about equally in males and females. Psoriasis occurs when skin
cells quickly rise from their origin below the surface of the skin and
pile up on the surface before they have a chance to mature. Usually this
movement (also called turnover) takes about a month, but in psoriasis
it may occur in only a few days. In its typical form, psoriasis results
in patches of thick, red (inflamed) skin covered with silvery scales.
These patches, which are sometimes referred to as plaques, usually itch
or feel sore. They most often occur on the elbows, knees, other parts of
the legs, scalp, lower back, face, palms, and soles of the feet, but
they can occur on skin anywhere on the body.
The disease may also affect the fingernails, the
toenails, and the soft tissues of the genitals and inside the mouth.
While it is not unusual for the skin around affected joints to crack,
approximately 1 million people with psoriasis experience joint
inflammation that produces symptoms of arthritis. This condition is
called psoriatic arthritis.