Scleroderma, also known as systemic sclerosis (SSc), is an autoimmune disease in which the body attacks its own tissues, causing inflammation and an overproduction of collagen. Collagen is a fiber-like protein that connects tissues together and an overproduction produces thickening and scarring (also called fibrosis) in involved tissues. Individuals with SSc usually have prominent thickening and stiffening of the skin (scleroderma) and may suffer from fatigue, weight loss, and joint swelling and/or pain. More severe forms of the disease involve internal organs such as the gastrointestinal tract, heart, lungs, and kidneys. Current estimates are that between 75,000 to 100,000 Americans have the disease. While SSc can present at any age, the onset of disease occurs most commonly in individuals 30–50 years old. SSc occurs more frequently in woman than men, and in African Americans than Caucasians.

Patients may be diagnosed with either limited cutaneous SSc (lcSSc) or diffuse cutaneous SSc (dcSSc), the determination being based on the extent of their skin disease. While the progression of disease is highly variable, patients with dcSSc typically progress more rapidly and have a worse prognosis. In dcSSc, involvement of internal organs, such as pulmonary fibrosis, often develops within the first three years whereas in lcSSc, Raynaud's phenomenon and skin involvement may precede other manifestations by years or even decades. As of now, no treatments have proven effective and SSc is associated with a significant risk of premature death. In one population-based study of SSc patients, the average survival after diagnosis was 11 years, with those diagnosed with lcSSc living longer than those with dcSSc. Lung involvement, including the development of pulmonary hypertension and/or fibrosis of the lungs, is currently the leading cause of medical complications and premature death and is the focus of the Scleroderma Lung Study.