ABSTRACT

Psoriasis has historically been considered an inflammatory skin disorder of unknown etiology producing red scaly patches of mere cosmetic nuisance to patients. “Psoriasis has a significant phenotypic variability,” with a range of clinical manifestations from mild disease with a few isolated plaques to multiple different morphological variants including guttate, discoid, annular, rupoid, and erythrodermic forms, with or without psoriatic joint disease. In 1963, Van Scott determined that there was a marked increase in mitoses/surface of psoriasis in comparison to the normal epidermis. Psoriasis is a highly symmetrical disease, but lesions on the scalp are frequently asymmetrical, almost certainly related to the inevitable koebnerization of scalp psoriasis due to the patient’s picking, scratching, and harsh shampooing. Psoriasis can be exacerbated or induced in some susceptible individuals by a number of systemic drugs. Psoriasis, especially in those patients with moderate to severe disease, should not be viewed as a minor cosmetic problem.