What is Scleroderma? Scleroderma is a group of rare diseases that involve the hardening and tightening of the skin and connective tissues — the fibers that provide the framework and support for your body. In some people, scleroderma affects only the skin. But in many people, scleroderma also harms structures beyond the skin — such as blood vessels, internal organs and the digestive tract. Signs and symptoms vary, depending on which structures are affected. What Are the Types