[Psoriasis today].

Abstract

PATHOGENESIS: Psoriasis is a proliferative disease of the epiderm which leads to major disorders in keratinocyte differentiation. The pathogenesis remains largely unknown. It has been hypothesized that intrinsic alterations of the keratinocyte or local or general immune disorders could be involved. GENES IMPLICATED: Psoriasis is a genodermatosis which is revealed or aggravated by environmental factors. The nature and chromosomal localization of the genes involved is currently under study. LOCAL TREATMENT: Over the last years, use of vitamin D has largely replaced former topical corticosteroid therapy. Phototherapy using narrow spectrum ultraviolet B is currently the standard treatment for extensive psoriasis. GENERAL TREATMENT: Methotrexate, retinoids and cyclosporin are effective in severe psoriasis but have side effects which limit their indications.