Psoriasis

Abstract

Psoriasis vulgaris is a common HLA-associated chronic, inflammatory disease of the skin and partly also of the connective tissue in the form of psoriatic arthritis. Psoriasis develops because of a complex genetic predisposition and has a familial occurrence that is often detectable over generations. Psoriasis also occurs without family background and known genetic associations. The skin lesions of psoriasis are sharply defined, silvery-white scaly erythematosquamous plaques in typical distribution. They result from increased inflammatory epidermopoiesis and can cover wide areas of the skin. In addition to the classic skin manifestations such as guttate psoriasis or plaque psoriasis, there are various generalized or localized special forms with or without pustules. A substantial number of psoriasis patients develop seronegative polyarthritis. Diseases frequently associated with psoriasis are inflammatory bowel disease and uveitis. Depending on its duration and severity, psoriasis also involves an independent risk of obesity, metabolic syndrome, cardiovascular disease, and increased mortality. Psoriasis is now considered to be a predominantly T-cell-mediated autoimmune disease in which activation of a certain functional type of autoreactive T cells against skin tissue cells causes chronic inflammation.