Psoriasis is a common skin condition that is widespread in western countries and parts of asia and africa. there are several types, most of which are difficult to control and flare up throughout life. red, thickened, scaly skin occurs in all types of psoriasis. the scaly areas do not always itch, but, if the condition affects many parts of the body, psoriasis may cause severe physical discomfort as well as embarrassment in public.

In areas of skin that are affected by psoriasis, new skin cells are produced at a much faster rate than dead cells are shed and the excess skin cells accumulate to form thick patches. the cause is not known, but an episode of psoriasis may be triggered by infection, injury, or stress. the condition often runs in families, which suggests that a genetic factor may be involved; approximately 1 in 3 people with psoriasis has a close relative who has the condition. the use of certain drugs, such as antidepressant drugs, antihypertensive drugs, beta blockers, and antimalarial drugs, can produce psoriasis in some people.