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What is scleroderma?

Scleroderma is an autoimmune disease of the connective tissue featuring skin thickening, spontaneous scarring, blood vessel disease, varying degrees of inflammation, associated with an overactive immune system. Autoimmune diseases are illnesses which 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 and organs of the body. This leads to thickness and firmness of involved areas. Scleroderma, when it's diffuse or widespread over the body, is also referred to as systemic sclerosis.

The cause of scleroderma is not known. Researchers have found some evidence that certain genes are important factors, but the environment seems to also play a role. The result is activation of the immune system in a susceptible individual, causing injury to tissues that result in injury similar to scar-tissue formation. The fact that genes seem to cause a predisposition to developing scleroderma means that inheritance at least plays a partial role. It is not unusual to find other autoimmune diseases in families of scleroderma patients. Some evidence for the role genes may play in leading to the development of scleroderma comes from the study of Choctaw Native Americans who are the group with the highest reported prevalence of the disease. The disease is more frequent in females than in males.

How is scleroderma classified?

Scleroderma can be classified in terms of the degree and location of the skin involvement. Accordingly, scleroderma has been categorized into two major groups, diffuse and limited. However, the terminology in the literature varies; for example, some investigators term the two major groups localized and systemic.

The diffuse form of scleroderma (systemic sclerosis) involves symmetric thickening of skin of the extremities, face, and trunk (chest, back, abdomen, or flanks) that can rapidly progress to hardening after an early inflammatory phase. Organ disease can occur early on and be serious. Organs affected include the esophagus, bowels, and lungs with scarring (fibrosis), heart, and kidneys. High blood pressure can be a troublesome side effect.

The limited form of scleroderma tends to have far less skin involvement with skin thickening confined to the skin of the fingers and face. The skin changes and other features of disease tend to occur more slowly than in the diffuse form. Because a characteristic clinical pattern can occur in patients with the limited form of scleroderma, this form has taken another name that is composed of the first initials of the common components. Thus, this form is also called the "CREST" variant of scleroderma. CREST represents the following features:

C...Calcinosis refers to the formation of tiny deposits of calcium in the skin. This is seen as hard, whitish areas in the superficial skin, commonly overlying the elbows, knees, or fingers. These firm deposits can be tender, can become infected, and can fall off spontaneously or require surgical removal. This is the least common of the CREST scleroderma variant features.

R...Raynaud's phenomenon refers to the spasm of the tiny artery vessels supplying blood to the fingers, toes, nose, tongue, or ears. These areas turns blue, white, then red after exposure to extremes of cold, or even sometimes with extremes of heat or emotional upset. This can lead to tiny areas of damage to the tips of the fingers (digital ulcers) or larger areas of dead skin on the ends of the fingers.

E...Esophagus disease in scleroderma is characterized by poorly functioning muscle of the lower two-thirds of the esophagus. This can lead to an abnormally wide esophagus that allows stomach acid to backflow into the esophagus to cause heartburn, inflammation, and potentially scarring that narrows the esophagus. This can eventually lead to difficulty in passing food from the mouth through the esophagus into the stomach. Symptoms of heartburn are treated aggressively in patients with scleroderma in order to prevent injury to the esophagus.

S...Sclerodactyly refers to the localized thickening and tightness of the skin of the fingers or toes. This can give them a "shiny" and slightly puffy appearance. The tightness can cause severe limitation of motion of the fingers and toes. These skin changes generally progress much slower that those of patients with the diffuse form of scleroderma.

T...Telangiectasias are tiny red areas, frequently on the face, hands, and in the mouth behind the lips. These areas blanch when they are pressed upon and represent widened (dilated) capillaries.

Patients can have variations of CREST, for example, CRST, REST, ST, etc. Patients can also have "overlap" illness with features of both CREST and the diffuse form of scleroderma. Some patients have overlaps of scleroderma and other connective tissue diseases, such as rheumatoid arthritis, systemic lupus erythematosus, and polymyositis. When features of scleroderma are present along with features of polymyositis and systemic lupus erythematosus, the condition is referred to as mixed connective tissue disease (MCTD).

Finally, scleroderma skin changes can be localized. Morphea is scleroderma skin that is localized to a patchy area of the skin that becomes hardened and slightly pigmented. Sometimes morphea can cause multiple lesions in the skin. Morphea is not associated with disease elsewhere in the body. Linear scleroderma is scleroderma that is localized usually to a lower extremity, frequently presenting as a strip of hardening skin down the leg of a child. Linear scleroderma in children can stunt bone growth of the affected limb. Sometimes linear scleroderma is associated with a "satellite" area of a patch of localized scleroderma skin, such as on the abdomen.