What is Psoriasis?
Psoriasis is a skin disease that usually contains raised, red patches covered with a build-up of dead skin cells. There are different forms of psoriasis (including plaque, guttate, inverse, pustular and erythrodermic). Psoriasis can also affect different areas of the body (including scalp psoriasis, genital psoriasis, psoriasis on the face, psoriasis on the hands and feet and psoriasis of the nails).
Usually people have only one type of psoriasis at a time. Sometimes psoriasis can change from one form of psoriasis to another. It is most likely to appear on the scalp, knees, elbows or torso, but it can develop anywhere on the body. Psoriasis is not infectious and cannot be caught from another person.
People suffering from psoriasis may develop psoriatic arthritis. It is similar to rheumatoid arthritis, but not as severe. It may affect the fingers, toes, neck, lower back, knees and ankles. In severe cases, it can cause irreversible damage to joints.
About fifty percent of people suffering from psoriasis develop scalp psoriasis. Scalp psoriasis is caused by the body producing too many skin cells on the scalp, resulting in red lesions covered with a white scale (made up of dead skin cells). In extreme cases of scalp psoriasis, thick plaques can cover the scalp and cause hair loss.
What Causes Psoriasis?
The exact cause of psoriasis is not known, but it is believed to be a genetic condition. It seems that the immune system speeds up the growth of new skin cells, so that the skin cells pile up. Often, there is something that triggers the immune system to act in this way and the resulting psoriasis. Some of the triggers that can cause psoriasis are: