Introduction Psoriasis is a noncontagious skin disorder that most commonly appears as inflamed swollen skin lesions covered with silvery white scale. Psoriasis comes in many different variations and degrees of severity. Select the following link to view photos and descriptions of the different types of psoriasis . Select the following link to view photos and descriptions of the different degrees of severity of psoriasis . No one knows what causes psoriasis, though it is generally accepted that it has a genetic component, and a recent study has established that it is an autoimmune skin disorder.
Scientists believe that a person is born genetically predisposed to psoriasis.
One in three people report a family history of psoriasis, but there is no pattern of inheritance. There are many cases in which children with no apparent family history of the disease will develop psoriasis. Once something triggers a person's genetic tendency to develop psoriasis, it is thought that in turn, the immune system triggers the excessive skin cell reproduction. In a normal growth pattern, skin cells are created in the basal cell layer, and then move up through the epidermis to the stratum corneum, the outermost layer of the skin. Dead cells are shed from the skin at about the same rate as new new cells are produced, maintaining a balance.