Scleroderma is an autoimmune condition of the connective tissue characterized by skin thickening, spontaneous scarring, blood vessel disease, and varying degrees of inflammation, associated with an overactive immune system.

Autoimmune diseases are illnesses that occur when the body's tissues are attacked by its own immune system. Scleroderma is characterized by the formation of scar tissue (fibrosis) in the skin. This leads to thickness and firmness of involved skin. This may also occur in internal organs such as the kidney.

Scleroderma is classified as localized or widespread (systemic scleroderma with a tendency to affect internal organs). Systemic scleroderma is further divided into limited and diffuse based upon the extent of skin involvement.