Epidemiology, Environmental, and Infectious Risk Factors

Systemic sclerosis (SSc) is an autoimmune connective tissue disease characterized by excessive collagen deposition in the skin and internal organs with associated vasculopathy and autoantibody production. Clinical classification of SSc is divided into two main groups: limited and diffuse cutaneous disease. The limited form is characterized by skin thickening that is confined to areas distal to the elbows and knees and generally is associated with less severe internal organ involvement. The diffuse form involves skin thickening proximal to the elbows and/or the knees as well as distal areas and is associated with more severe organ damage. This chapter will focus on the epidemiology of systemic sclerosis including both limited and diffuse cutaneous forms along with inborn/genetic and acquired/environmental risk factors.