Systemic scleroderma, or systemic sclerosis, is an autoimmune rheumatic disease characterised by excessive production and accumulation of collagen, called fibrosis, in the skin and internal organs and by injuries to small arteries. Scleroderma is a group of rare diseases that more often affects women. It commonly occurs between the ages of 30 and 50. Symptoms include tightening of the skin, joint pain, exaggerated response to cold and heartburn. Systemic sclerosis (SS) is an autoimmune disorder. This means it's a condition in which the immune system attacks the body. Healthy tissue is destroyed because the immune system mistakenly thinks it's a foreign substance or infection. Collagen is a component of connective tissue.