Scleroderma's signs and symptoms vary, depending on which parts of your body are affected:

• Skin. Nearly everyone who has scleroderma experiences a hardening and tightening of patches of skin. These patches may be shaped like ovals or straight lines, or cover wide areas of the trunk and limbs. The number, location and size of the patches vary by type of scleroderma. Skin can appear shiny because it's so tight, and movement of the affected area may be restricted.
• Fingers or toes. One of the earliest signs of systemic scleroderma is Raynaud's disease, which causes the small blood vessels in your fingers and toes to contract in response to cold temperatures or emotional distress. When this happens, your fingers or toes may turn blue or feel painful or numb. Raynaud's disease also occurs in people who don't have scleroderma.
• Digestive system. Scleroderma can cause a variety of digestive symptoms, depending on which part of the digestive tract is affected. If the esophagus is affected, you might have heartburn or difficulty swallowing. If the intestines are affected, you might have cramps, bloating, diarrhea or constipation. Some people who have scleroderma may also have problems absorbing nutrients if their intestinal muscles aren't properly moving food through the intestines.
• Heart, lungs or kidneys. Scleroderma can affect the function of the heart, lungs or kidneys to varying degrees. These problems, if left untreated, can become life-threatening.

Scleroderma results from an overproduction and accumulation of collagen in body tissues. Collagen is a fibrous type of protein that makes up your body's connective tissues, including your skin.

Doctors don't know exactly what causes the abnormal collagen production to begin, but the body's immune system appears to play a role. Most likely, scleroderma is caused by a combination of factors, including immune system problems, genetics and environmental triggers.

Anyone can get scleroderma, but it does occur much more often in women than in men. Several combined factors appear to influence the risk of developing scleroderma:

• Genetics. People who have certain gene variations appear to be more likely to develop scleroderma. This may explain why a small number of scleroderma cases appear to run in families and why certain types of scleroderma are more common for certain ethnic groups. For example, Choctaw Native Americans are more likely to develop the type of scleroderma that affects internal organs.
• Environmental triggers. Research suggests that, in some people, scleroderma symptoms may be triggered by exposure to certain viruses, medications or drugs. Repeated exposure — such as at work — to certain harmful substances or chemicals also may increase the risk of scleroderma.
• Immune system problems. Scleroderma is believed to be an autoimmune disease. This means that it occurs in part because the body's immune system begins to attack the connective tissues. In 15 to 20 percent of cases, a person who has scleroderma also has symptoms of another autoimmune disease, such as rheumatoid arthritis, lupus or Sjogren's syndrome.

Scleroderma complications range from mild to severe and can affect your:

• Fingertips. The variety of Raynaud's disease that occurs with systemic scleroderma can be so severe that the restricted blood flow permanently damages the tissue at the fingertips, causing pits or skin sores. In some cases, the tissue on the fingertips may die and require amputation.
• Lungs. Scarring of lung tissue can result in reduced lung function, which can impact your ability to breathe and tolerance for exercise. You may also develop high blood pressure in the arteries to your lungs.
• Kidneys. When scleroderma affects your kidneys, you can develop elevated blood pressure and an increased level of protein in your urine. More-serious effects of kidney complications may include renal crisis, which involves a sudden increase in blood pressure and rapid kidney failure.
• Heart. Scarring of heart tissue increases your risk of abnormal heartbeats and congestive heart failure, and can cause inflammation of the membranous sac surrounding your heart. Scleroderma can also raise the pressure on the right side of your heart and cause it to wear out.
• Teeth. Severe tightening of facial skin can cause your mouth to become smaller and narrower, which may make it hard to brush your teeth or to even have them professionally cleaned. People who have scleroderma often don't produce normal amounts of saliva, so the risk of dental decay increases even more.
• Digestive system. Digestive problems associated with scleroderma can lead to heartburn and difficulty swallowing. It can also cause bouts of cramps, bloating, constipation or diarrhea.
• Sexual function. Men who have scleroderma may experience erectile dysfunction. Scleroderma may also affect the sexual function of women by decreasing sexual lubrication and constricting the vaginal opening.