Scleroderma affects the skin and connective tissue, according to the Scleroderma Foundation. It may also affect the muscles, joints and internal organs, depending upon the kind of scleroderma, its location and how extensive it is.
The foundation names two main kinds of scleroderma: localized and systemic. Localized scleroderma mostly involves hardening of the skin and the soft flesh underneath, including muscle. Systemic scleroderma involves the connective tissue found throughout the body. The digestive and respiratory tracts may be affected as well as blood vessels, muscles and joints. Rarely, organs such as the heart, kidneys, or lungs are damaged by the disease. Even in systemic scleroderma, the skin is often affected, especially the skin over the fingers and toes, adds Mayo Clinic.