- MEDICAL CONDITION
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.
Anyone can get psoriasis, but it occurs more often in adults. In many cases, 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.
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.
Psoriasis can be hard to diagnose because it can look like other skin diseases. The doctor might need to look at a small skin sample under a microscope.