Psoriasis is a chronic (long-lasting) skin disease that causes raised, red patches on your skin. The raised patches may have silvery scales.
Psoriasis is common and can run in families
Light-skinned people get psoriasis more often than dark-skinned people
Psoriasis usually starts when you're between ages 16 and 22 years or between ages 57 and 60 years
The patches can be large or small, and they can appear anywhere on your body, especially your elbows, knees, and scalp
Psoriasis can’t be cured, but the patches can go away for long periods of time and then come back
Doctors treat psoriasis with phototherapy (shining a UV light on your skin to heal it) and medicine
Doctors aren’t sure exactly what causes psoriasis. It may be a problem with your immune system (the cells, tissues, and organs that protect your body from illness and infection). Psoriasis tends to run in families. That means if you have psoriasis some of your relatives may also have psoriasis.
Psoriasis tends to come and go, although some patches may never go away. Flare-ups are when it comes back or gets worse. Flare-ups can be triggered by:
Flare-ups are more common for people who are overweight, smoke tobacco, or have HIV infection.
The skin patches may:
The patches may itch or hurt. You may be bothered by the way they look.
Some people with psoriasis have other symptoms, such as swollen, painful joints or pus-filled blisters.