The types of scleroderma, a condition where connective tissue in the skin and sometimes between internal organs grows abnormally, can be broken down into two main categories. When only a portion of the body is affected, this is known as localized scleroderma. This type can be further broken down into linear, where a band of skin is affected, and morphea, in which patches of skin can become red, thick, and firm. The other main classification is systemic scleroderma, or systemic sclerosis, which occurs throughout the body. Systemic scleroderma also has two underlying categories, limited and diffuse, though some doctors consider there to be a third category called sine, where the skin is not involved.
Localized scleroderma occurs in the skin and sometimes its underlying tissue and muscles, and typically gets better in time, though it may cause permanent damage to the affected areas. The first of these types of scleroderma, morphea, is characterized by oval patches where the skin is thickened and firm and is colored red with violet borders. These patches do not produce sweat or hair and can occur almost anywhere on the body, including the torso, arms, legs, or face. Morphea may be localized to a small area of the body or become generalized and cover large parts of the skin.
The other of the localized types of scleroderma is linear. With this condition, the thick, discolored skin forms a line or band. It often runs down a person's arm or leg, though in some cases it is found on the forehead.
When the blood vessels or internal organs become involved, scleroderma is considered to be of the systemic variety. The more common form is limited scleroderma, which mainly involves the skin and blood vessels in the hands, arms, legs, and face. This condition is also sometimes called CREST syndrome, since many patients display one or more symptoms associated with that acronym. These five symptoms are calcinosis, Raynaud's phenomenon, esophageal dysfunction, sclerodactyly, and telangiectasias. The onset of limited scleroderma typically occurs over several years, with the Raynaud's symptoms affecting the blood vessels often occurring years before the skin starts to thicken.
In contrast, the second of the systemic types of scleroderma, diffuse, usually comes on rapidly. Much of the skin on the body is affected immediately, and the condition can also start to damage organs such as the heart, kidneys, and lungs. This will typically continue for several years before patients finally stabilize, at which point they may even see some improvement.