What is psoriasis?

➢ Psoriasis is a T cell-mediated inflammatory disease, presumed to be autoimmune in origin, although the antigens are not well described. ➢ It is unclear whether the inciting antigens are self-antigens, environmental antigens, or some combination of the two. ➢ Psoriatic lesions can be induced in susceptible individuals by local trauma (Koebner phenomenon), which may induce a local inflammatory response that promotes lesion development.