Psoriasis is a noncontagious skin condition that produces plaques of thickened, scaling skin. The dry scales are thought to result from the rapid proliferation of skin cells triggered by the release of inflammatory chemicals from abnormal blood lymphocytes. Psoriasis commonly affects the skin of the elbows, knees, and scalp. Some people have such mild psoriasis that they may not even suspect that they have a medical skin condition. Others have very severe psoriasis involving their entire body. Psoriasis is an incurable, long-term (chronic) skin condition. It has a variable course, periodically improving and worsening. It is not unusual for psoriasis to spontaneously clear for years and stay in remission. Many people note a worsening of their symptoms in the colder winter months.
The exact cause remains unknown. There may be a combination of factors, including genetic predisposition and environmental factors. It is common for psoriasis to be found in members of the same family. Defects in the immune system are thought to play a major role. Despite research over the past 30 years looking at many triggers, the
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