Systemic sclerosis is an autoimmune connective tissue disease that affects the skin, blood vessels, and internal organs. There are two major subtypes: limited, characterized by skin changes limited to the hands, face, and CREST syndrome features; and diffuse, with generalized skin thickening that spreads from the hands and arms. Systemic involvement can include pulmonary fibrosis/hypertension, gastrointestinal dysmotility, renal crisis, cardiac and musculoskeletal issues. The pathogenesis involves vascular dysfunction, immune dysregulation, and excessive fibrosis. Diagnosis is based on characteristic skin changes and internal organ involvement. Prognosis depends on the specific organ systems affected.