The disease is called scleroderma, and no one is sure what causes it or how it can be cured.

An estimated 200 to 300 people per million in the United States suffer from scleroderma, according to the American College of Rheumatology. Some 12 to 20 new cases per million are diagnosed annually.

Scleroderma is believed to be an autoimmune disease, in which the immune system turns against one's own body.

"Your body attacks itself," said Dr. Peter A. Merkel, an associate professor of medicine in the rheumatology section at Boston University School of Medicine, and a doctor with the school's scleroderma program.

It's not known what prompts the immune system attack, although researchers believe it is probably caused by a genetic predisposition interacting with some environmental stimulus.

"We know it's not likely to be a single cause, which makes research more challenging," said Carol Feghali-Bostwick, an assistant professor of medicine in the division of pulmonary, allergy and critical medicine at the University of Pittsburgh's Simmons Center for Interstitial Lung Disease.

The immune system is believed to stimulate cells called fibroblasts, causing them to produce too much collagen, according to the National Institute of Arthritis and Musculoskeletal and Skin Diseases. The collagen builds up thick connective tissue within the skin and internal organs that can interfere with their function.

Localized scleroderma can take the form of reddish patches of skin that thicken into firm, oval-shaped areas. The center of each patch becomes ivory colored with violet borders. The patches appear most often on the chest, stomach and back, but also can appear on the face, arms and legs. They sweat very little and have little hair growth.

As the disease progresses, the skin grows thicker. "It can affect your movement," Merkel said. "It can affect your ability to move your hands in a functional way. The skin on your face becomes very tight. It can change people's appearance."

The thickening can also spread, becoming systemic. The fingers, hands, face, lower arms and legs are the only places affected if the spread is limited, but people also can suffer a range of symptoms doctors refer to as CREST, according to the National Institutes of Health.

CREST stands for:

• Calcinosis, the formation of calcium deposits in the connective tissues, usually found on the fingers, hands, face, and trunk, and on the skin above the elbows and knees. Painful ulcers can result if the deposits break through the skin.
• Raynaud's phenomenon, a condition in which the small blood vessels of the hands or feet contract in response to cold or anxiety. Fingertips may suffer damage that leads to ulcers, scars, or gangrene.
• Esophageal dysfunction, which occurs when smooth muscles in the esophagus lose normal movement. The result can be swallowing difficulties, chronic heartburn or inflammation.
• Sclerodactyly, or thick and tight skin on the fingers resulting from deposits of excess collagen within skin layers. It becomes hard to bend or straighten fingers, and the skin may also appear shiny and darkened.
• Telangiectasia, a condition caused by the swelling of tiny blood vessels. Small red spots appear on the hands and face.

In the most serious cases, internal organs are affected. Kidneys quit working. Lungs stiffen, making it hard to take a breath. Hearts are unable to pump as efficiently.

In general, doctors treat scleroderma by treating the complications it causes, Feghali-Bostick said.

"People with lung problems are going to be treated for lung problems," she said. "People with kidney problems will be treated with drugs to prevent kidney failure."

One of the success stories in scleroderma treatment involves new autoimmune drugs that preserve kidney function. People with scleroderma used to die mainly from kidney disease, Merkel said, but these days they are more likely to die of lung problems.

"We have a very effective treatment for the kidney disease, and it's really changed the course of the kidney disease," Merkel said. "We have good treatment for heartburn and gastrointestinal problems. We have some treatment with immunosuppressive therapies with lungs. But we don't have great treatment for the skin, which is the cardinal treatment of the disease."

Feghali-Bostick hopes that increased attention will turn to this disease, and with that attention increased funding to help solve its riddles.

"Scleroderma is not less frequent than multiple sclerosis, but MS gets 10 times more funding," she said.

More information

To learn more, visit the Scleroderma Foundation.