Forms of Scleroderma
There are two major classifications of scleroderma: localized scleroderma and systemic sclerosis (SSc). Other forms or sub classifications, each with its own characteristics and prognosis, may be identified through future research.
Localized Scleroderma The changes, which occur in localized scleroderma, are usually found in only a few places on the skin or muscles, and rarely spread elsewhere. Generally, localized scleroderma is relatively mild. The internal organs are usually not affected, and persons with localized scleroderma rarely develop systemic scleroderma. Some laboratory abnormalities commonly seen in systemic scleroderma are frequently absent in the localized form.
- Morphea is a form of localized scleroderma characterized by waxy patches on the skin of varying sizes, shapes and color. The skin under the patches may thicken. The patches may enlarge or shrink, and often may disappear spontaneously. Morphea usually appears between the ages of 20 and 50, but is often seen in young children.
- Linear scleroderma is a form of localized scleroderma which frequently starts as a streak or line of hardened, waxy skin on an arm or leg or on the forehead. Sometimes it forms a long crease on the head or neck, referred to as en coup de sabre because it resembles a saber or sword wound. Linear scleroderma tends to involve deeper layers of the skin as well as the surface layers, and sometimes affects the motion of the joints, which lie underneath. Linear scleroderma usually develops in childhood. In children, the growth of involved limbs may be affected.
Systemic scleroderma (systemic sclerosis) may affect the connective tissue in many parts of the body. Systemic scleroderma can involve the skin, esophagus, gastrointestinal tract (stomach and bowels), lungs, kidneys, heart and other internal organs. It can also affect blood vessels, muscles and joints. The tissues of involved organs become hard and fibrous, causing them to function less efficiently. The term systemic sclerosis indicates that “sclerosis” (hardening) may occur in the internal systems of the body. There are two major recognized patterns that the illness can take – diffuse or limited disease. In diffuse scleroderma, skin thickening occurs more rapidly and involves more skin areas than in limited disease. In addition, people with diffuse scleroderma have a higher risk of developing “sclerosis” or fibrous hardening of the internal organs.
About half of people diagnosed have a slower progressing and more benign illness called limited scleroderma. In limited scleroderma, skin thickening is less widespread, typically confined to the fingers, hands and face, and develops slowly over years. Although internal problems occur, they are less frequent and tend to be less severe than in diffuse scleroderma and are usually delayed in onset for several years. However, persons with limited scleroderma, and occasionally those with diffuse scleroderma, can develop pulmonary hypertension, a condition in which the lung’s blood vessels become narrow, leading to impaired blood flow through the lungs resulting in shortness of breath.
Limited scleroderma is sometimes called CREST syndrome. CREST stands for the initial letters of five common features:
- Raynaud Phenomenon
- Esophageal dysfunction
To further complicate the terminology, some people with diffuse disease will go on to develop calcinosis and telangiectasias so that they also have the features of CREST.
Although most people can be classified as having diffuse or limited disease, different people may have different symptoms and/or a different combination of symptoms of the illness.