african american doctor and nursePsoriasis is a skin disease that causes scaling and swelling. Skin
cells grow deep in the skin and slowly rise to the surface. This process is
called cell turnover, and it takes about a month. With psoriasis, it can happen
in just a few days because the cells rise too fast and pile up on the surface.

Most psoriasis causes patches of thick, red skin with silvery
scales. These patches can itch or feel sore. They are often found on the elbows,
knees, other parts of the legs, scalp, lower back, face, palms, and soles of the
feet. But they can show up other places such as fingernails, toenails, genitals,
and inside the mouth.

Who Gets Psoriasis?

Anyone can get psoriasis, but it occurs more often in adults.
Sometimes there is a family history of psoriasis. Certain genes have been linked
to the disease. Men and women get psoriasis at about the same rate.

What Causes Psoriasis?

Psoriasis begins in the immune system, mainly with a type of white
blood cell called a T cell. T cells help protect the body against infection and
disease. With psoriasis, T cells are put into action by mistake. They become so
active that they set off other immune responses. This leads to swelling and fast
turnover of skin cells. People with psoriasis may notice that sometimes the skin
gets better and sometimes it gets worse. Things that can cause the skin to get
worse include: