In patients with scleroderma, the immune system triggers other cells to produce too much collagen (a protein). This extra collagen is deposited in the skin and organs, which causes hardening and thickening (similar to the scarring process). Also known as systemic sclerosis. It is an autoimmune chronic connective disease that causes inflammation in the skin and other places in the body. This inflammation causes the body to make too much collagen, which leads to visible hardening of the skin and damage to your blood vessels and other internal organs, such as the heart, lungs, and kidneys.