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Derived from the Greek words "sklerosis," meaning hardness, and "derma," meaning skin, scleroderma literally means hard skin. Though it is often referred to as if it were a single disease, scleroderma is really a symptom of a group of diseases that involve the abnormal growth of connective tissue, which supports the skin and internal organs. It is sometimes used, therefore, as an umbrella term for these disorders. In some forms of scleroderma, hard, tight skin is the extent of this abnormal process. In other forms, however, the problem goes much deeper, affecting blood vessels and internal organs, such as the heart, lungs, and kidneys.
Scleroderma is called both a rheumatic disease and a connective tissue disease. The term rheumatic disease refers to a group of conditions characterized by inflammation and/or pain in the muscles, joints, or fibrous tissue. A connective tissue disease is one that affects tissues such as skin, tendons, and cartilage.
Estimates for the number of people in the United States with systemic sclerosis range from 40,000 to 165,000. By contrast, a survey that included all scleroderma-related disorders, including Raynaud’s phenomenon, suggested a number between 250,000 and 992,500.
Symptoms of Different Types
The group of diseases we call scleroderma falls into two main classes: localized scleroderma and systemic sclerosis. Localized diseases affect only certain parts of the body; systemic diseases can affect the whole body. Both groups include subgroups. Although there are different ways these groups and subgroups may be broken down or referred to, the following is a common way of classifying these diseases:
Localized types of scleroderma are those limited to the skin and related tissues and, in some cases, the muscle below. Internal organs are not affected by localized scleroderma, and localized scleroderma can never progress to the systemic form of the disease. Often, localized conditions improve or go away on their own over time, but the skin changes and damage that occur when the disease is active can be permanent. For some people, localized scleroderma is serious and disabling.
There are two generally recognized types of localized scleroderma:
Morphea: Morphea comes from a Greek word that means "form" or "structure." The word refers to local patches of scleroderma. The first signs of the disease are reddish patches of skin that thicken into firm, oval-shaped areas. The center of each patch becomes ivory colored with violet borders. These patches sweat very little and have little hair growth. Patches appear most often on the chest, stomach, and back. Sometimes they appear on the face, arms, and legs.
Morphea can be either localized or generalized. Localized morphea limits itself to one or several patches, ranging in size from a half-inch to 12 inches in diameter. The condition sometimes appears on areas treated by radiation therapy. Some people have both morphea and linear scleroderma (described below). The disease is referred to as generalized morphea when the skin patches become very hard and dark and spread over larger areas of the body. Regardless of the type, morphea generally fades out in 3 to 5 years; however, people are often left with darkened skin patches and, in rare cases, muscle weakness.
Linear scleroderma: As suggested by its name, the disease is characterized by a single line or band of thickened and/or abnormally colored skin. Usually, the line runs down an arm or leg, but in some people it runs down the forehead. People sometimes use the French term en coup de sabre, or "sword stroke," to describe this highly visible line.
Systemic Scleroderma (Systemic Sclerosis)
This is the term for the form of the disease that not only includes the skin, but also involves the tissues beneath, the blood vessels, and the major organs. Systemic sclerosis is typically broken down into limited cutaneous scleroderma and diffuse cutaneous scleroderma. Some doctors break systemic sclerosis down into a third subset called systemic sclerosis sine (Latin for "without" scleroderma. This means that patients have other manifestations of scleroderma but they do not have any overt skin thickening.
Limited cutaneous scleroderma
Limited cutaneous scleroderma typically comes on gradually and affects the skin only in certain areas: the fingers, hands, face, lower arms, and legs. Most people with limited disease have Raynaud’s phenomenon for years before skin thickening starts. Telangiectasias and calcinosis often follow. (See definitions below.) Gastrointestinal involvement occurs commonly and some patients have severe lung problems, even though the skin thickening remains limited. People with limited disease often have all or some of the symptoms that some doctors call CREST, which stands for the following:
Diffuse cutaneous scleroderma
This condition typically comes on suddenly. Skin thickening begins in the hands and spreads quickly and over much of the body, affecting the hands, face, upper arms, upper legs, chest, and stomach in a symmetrical fashion (for example, if one arm or one side of the trunk is affected, the other is also affected). Some people may have more area of their skin affected than others. Internally, it can damage key organs such as the intestines, lungs, heart, and kidneys.
People with diffuse disease often are tired, lose appetite and weight, and have joint swelling and/or pain. Skin changes can cause the skin to swell, appear shiny, and feel tight and itchy.
The damage of diffuse scleroderma typically occurs over a few years. After the first 3 to 5 years, people with diffuse disease often enter a stable phase lasting for varying lengths of time. During this phase, symptoms subside: joint pain eases, fatigue lessens, and appetite returns. Progressive skin thickening and organ damage decrease.
Gradually, however, the skin may begin to soften, which tends to occur in reverse order of the thickening process: the last areas thickened are the first to begin softening. Some patients" skin returns to a somewhat normal state, while other patients are left with thin, fragile skin without hair or sweat glands. Serious new damage to the heart, lungs, or kidneys is unlikely to occur, although patients are left with whatever damage they have in specific organs.
People with diffuse scleroderma face the most serious long-term outlook if they develop severe kidney, lung, digestive, or heart problems. Fortunately, less than onethird of patients with diffuse disease develop these severe problems. Early diagnosis and continual and careful monitoring are important.
A diagnosis of scleroderma is based largely on the medical history and findings from the physical exam. Finding one or more of the following factors can help the doctor diagnose a certain form of scleroderma:
The doctor may order lab tests to help confirm a suspected diagnosis. At least two proteins, called antibodies, are commonly found in the blood of people with scleroderma:
A number of other scleroderma-specific antibodies can occur in people with scleroderma, although less frequently. When present, however, they are helpful in clinical diagnosis and may give additional information as to the risks for specific organ problems.
Because not all people with scleroderma have these antibodies and because not all people with the antibodies have scleroderma, lab test results alone cannot confirm the diagnosis.
In some cases, the doctor may order a skin biopsy (the surgical removal of a small sample of skin for microscopic examination) to aid in or help confirm a diagnosis. However, skin biopsies, too, have their limitations: biopsy results cannot distinguish between localized and systemic disease, for example.
Diagnosing scleroderma is easiest when a person has typical symptoms and rapid skin thickening. In other cases, a diagnosis may take months, or even years, as the disease unfolds and reveals itself and as the doctor is able to rule out some other potential causes of the symptoms. In some cases, a diagnosis is never made, because the symptoms that prompted the visit to the doctor go away on their own.
Although scientists don’t know exactly what causes scleroderma, they are certain that people cannot catch it from or transmit it to others. Studies of twins suggest it is also not inherited. Scientists suspect that scleroderma comes from several factors that may include:
Abnormal immune or inflammatory activity: Like many other rheumatic disorders, scleroderma is believed to be an autoimmune disease. An autoimmune disease is one in which the immune system, for unknown reasons, turns against one’s own body.
In scleroderma, the immune system is thought to stimulate cells called fibroblasts so they produce too much collagen. The collagen forms thick connective tissue that builds up within the skin and internal organs and can interfere with their functioning. Blood vessels and joints can also be affected.
Genetic makeup: While genes seem to put certain people at risk for scleroderma and play a role in its course, the disease is not passed from parent to child like some genetic diseases.
Environmental triggers: Research suggests that exposure to some environmental factors may trigger sclerodermalike disease (which is not actually scleroderma) in people who are genetically predisposed to it. Suspected triggers include viral infections, certain adhesive and coating materials, and organic solvents such as vinyl chloride or trichloroethylene. But no environmental agent has been shown to cause scleroderma. In the past, some people believed that silicone breast implants might have been a factor in developing connective tissue diseases such as scleroderma. But several studies have not shown evidence of a connection.
Hormones: By the middle to late childbearing years (ages 30 to 55) women develop scleroderma 7 to 12 times more often than men. Because of female predominance at this and all ages, scientists suspect that hormonal differences between women and men play a part in the disease. However, the role of estrogen or other female hormones has not been proven.