Psoriasis is a skin disease that affects more
than 4 million persons in the United States. Besides causing skin problems,
psoriasis can lead to problems with joints, fingernails and toenails, genitals,
and inside of the mouth. The most common form of psoriasis leaves patches
of scaly, red skin, usually on the elbows, knees, scalp, lower back, or face,
but any place on the body may be affected. These scaly patches are called plaques. The amount of affected skin varies considerably
among different individuals. Some persons develop pain, stiffness, and swelling
in their joints (for example, the knees, wrists, or elbows) associated with
psoriasis called psoriatic arthritis.Scientists have
found that psoriasis is a genetic or inherited disease that affects the body's immune (disease-fighting) system. Infections, stress, and
some medications may worsen the psoriasis disease process. Psoriasis is not
contagious. The December 17, 2003, issue of JAMA includes
an article about treatment of psoriasis in persons with extensive skin disease.