The word scleroderma literally means "hard skin." It is an uncommon autoimmune connective tissue disease that affects small blood vessels and causes excess collagen accumulation. Cold fingers (Raynaud’s Phenomenon) is often the first symptom.
The most characteristic feature of scleroderma is the presentation of hard, hide-bound thickening of the skin. Less visible but of major importance are the lesions that occur in small blood vessels (vascular lesions), which may involve major organs.
The natural history, or course of scleroderma, varies widely from that of a mild nuisance to a severe multi-system disease. Forms of the disease that primarily affect the skin without major organ involvement, have better long-term outlook. Those forms of scleroderma that involve major organs, such as the heart and kidney, are potentially more severe with possibly less desirable long-term outcomes.
Scleroderma is an autoimmune disease which means that it is a condition in which the body’s immune system attacks its own tissues. The normal role of the immune system is to provide protection from invaders such as viruses. In autoimmune disorders, the ability to distinguish foreign from self is compromised. As immune cells attack the body’s own tissue, inflammation and damage result. Scleroderma can vary a great deal in terms of severity. For some, it is a mild condition; for others it can be life-threatening. There are medications to slow down disease progression and help with symptoms, but as of yet, there is no cure for scleroderma.
The National Institute of Arthritis and Musculoskeletal and Skin Disease, recognizes that although scleroderma is often referred to as if it were a single disease, in fact, it is really a symptom of a group of diseases that involve the irregular growth of collagen. Collagen forms the cellular matrix of connective tissue found in skin, tendons, ligaments, cartilage, bone, blood vessels, the gut and other internal organ surfaces. In some forms of scleroderma, hard, tight skin is the extent of this irregular collagen over-production process. In other forms, however, the problem goes much deeper, and may severely affect blood vessels and internal organs such as the heart, lungs, and kidneys.
The cause of scleroderma is unknown. However, we do understand a great deal about the biological processes involved. In localized scleroderma, the underlying problem is the overproduction of collagen (scar tissue) in the involved areas of skin. In systemic sclerosis, there are three processes at work: vascular disease, fibrosis (which is an overproduction of collagen) and autoimmunity (or immune system dysfunction) which leads to inflammation.
In systemic sclerosis the small blood vessels are damaged and become narrowed. This is what is responsible for Raynaud’s Phenomenon and the painful ulcers that can occur on the fingers. This vascular damage also occurs in the internal organs and is responsible for scleroderma renal crisis and pulmonary hypertension. The small arteries are normally capable of constricting (narrowing) or dilating (relaxing) to adjust blood flow to the needs of the body. For example, in very cold weather the blood vessels to the hands and feet narrow in order to maintain central body warmth. In systemic sclerosis, however, the blood vessel loses its normal method of relaxation, becoming prone to episodes of vasospasm (contraction of the muscle wall that closes the vessel). The vessels become overly sensitive to cold temperatures and other stimuli like emotional stress, which results in Raynaud’s attacks.
The thickened skin in scleroderma is caused by overproduction of collagen, which is the basic component of scar tissue. Collagen is made by fibroblasts (a type of cell that is part of every tissue in the body) which can be provoked or activated to make more collagen. Fibroblasts are activated by the immune system to produce collagen as part of the normal healing process. Under normal circumstances, the production of a scar is the last step in healing following an injury or an infection. Abnormal accumulation of collagen is called fibrosis. Although collagen is a normal part of skin and many organs, in scleroderma, the balance of collagen formation and collagen breakdown is altered so that too much collagen builds up. In localized scleroderma this process is confined to some areas of the skin. In systemic sclerosis, excess collagen causes fibrosis in the heart, lungs, and the muscles that line the gastrointestinal tract.
The third problem in systemic sclerosis is the dysregulation of the immune system resulting in an immune attack on the body’s own tissues leading to inflammation. Some of these autoantibodies are found in several autoimmune diseases, while others are specific for a particular disease. One way to detect activation of the immune system is to find antibodies (proteins made by immune cells, the bullets of our immune army) in the blood that target the body’s own tissue (autoantibodies). A very specific set of autoantibodies is found in scleroderma. These autoantibodies can be thought of as footprints of the scleroderma disease process because they are only made under very specific conditions. It is not clear what role these autoantibodies play in damaging the blood vessels or stimulating collagen overproduction.
Scientists are certain that scleroderma is not contagious, not infectious, and not cancerous. Studies of twins also suggest that scleroderma is not inherited.
Although scleroderma is more common in women, with an average age of disease onset around 40 years, scleroderma also occurs in men and children, from infants to the elderly. It affects people of all races and ethnic groups. However, there are some patterns by disease type across populations of people, such as: