Psoriasis (say "suh-RY-uh-sus")
is a long-term (chronic) skin problem that causes skin cells to grow too
quickly, resulting in thick, white, silvery, or red patches of skin.
skin cells grow gradually and flake off about every 4 weeks. New skin cells
grow to replace the outer layers of the skin as they shed.
But in psoriasis ,
new skin cells move rapidly to the surface of the skin in days rather than
weeks. They build up and form thick patches called plaques (say "plax"). The patches range in size from small to large. They most often appear on
the knees, elbows, scalp, hands, feet, or lower back. Psoriasis is most common
in adults. But children and teens can get it too.
psoriasis can be embarrassing, and many people, especially teens, avoid
swimming and other situations where patches can show. But there are many types
of treatment that can help keep psoriasis under control.
Experts believe that
psoriasis occurs when the
immune system overreacts, causing
inflammation and flaking of skin. In some
cases, psoriasis runs in families.
psoriasis often notice times when their skin gets worse. Things that can cause
these flare-ups include a cold and dry climate, infections,
stress, dry skin, and taking certain medicines.
Psoriasis isn't contagious. It
can't be spread by touch from person to person.
Symptoms of psoriasis
appear in different ways. Psoriasis can be mild, with small areas of rash. When
psoriasis is moderate or severe, the skin gets inflamed with raised red areas
topped with loose, silvery, scaling skin. If psoriasis is severe, the skin
becomes itchy and tender. And sometimes large patches form and may be uncomfortable. The patches can join together and cover large areas of skin, such
as the entire back.
In some people, psoriasis causes joints to
become swollen, tender, and painful. This is called
psoriatic arthritis (say "sor-ee-AT-ik ar-THRY-tus").
This arthritis can also affect the fingernails and toenails, causing the nails
to pit, change color, and separate from the nail bed. Dead skin may build up
under the nails.
Symptoms often disappear (go into remission),
even without treatment, and then return (flare up).