Psoriasis: epidemiology, natural history, and differential diagnosis

Abstract

Juliana L Basko-Plluska, Vesna Petronic-RosicDepartment of Medicine, Section of Dermatology, University of Chicago, Chicago, IL, USAAbstract: Psoriasis is a chronic, immune-mediated, inflammatory disease which affects primarily the skin and joints. It occurs worldwide, but its prevalence varies considerably between different regions of the world. Genetic susceptibility as well as environmental factors play an important role in determining the development and prognosis of psoriasis. Genome-wide association studies have identified many genetic loci as potential psoriasis susceptibility regions, including PSORS1 through PSORS7. Histocompatibility antigen (HLA) studies have also identified several HLA antigens, with HLA-Cw6 being the most frequently associated antigen. Epidemiological studies identified several modifiable risk factors that may predispose individuals to developing psoriasis or exacerbate pre-existing disease. These include smoking, obesity, alcohol consumption, diet, infections, medications and stressful life events. The exact mechanism by which they trigger psoriasis remains to be elucidated; however, existing data suggest that they are linked through Th1-mediated immunological pathways. The natural history of psoriasis varies depending on the clinical subtype as well as special circumstances, including pregnancy and HIV infection. In general, psoriasis is a chronic disease with intermittent remissions and exacerbations. The differential diagnosis is vast and includes many other immune-mediated, inflammatory disorders.Keywords: psoriasis, epidemiology, natural history, differential diagnosis