Scleroderma is a connective tissue disease characterized by localized or diffuse fibrosis, sclerosis and atrophy of connective tissue of the skin and internal organs. Its main characteristics are fibrosis or sclerosis of the skin, synovium, skeletal muscle, blood vessels and esophagus. Some internal organs, such as the lungs, heart, kidneys and large and small arteries, may also have similar lesions. Some patients only have skin sclerosis, which is called localized scleroderma; while some patients also have fibrosis and sclerosis of the heart, lungs, gastrointestinal tract and kidneys. This situation is called systemic scleroderma, which is often serious and has a poor prognosis. This disease ranks second only to lupus erythematosus among connective tissue diseases. There are more female patients, with a ratio of about 3:1 between female and male. The age of onset is more common between 20 and 50 years old. The disease is most common in women of childbearing age, and children and the elderly can also get sick. It has been reported that miners and workers exposed to silicon have more patients with scleroderma.