Scleroderma is a rare disease in which a person's immune system begins to destroy normal, healthy tissues. (This is called an autoimmune disease.) As a result, connective tissue of the skin, lungs, and internal organs—especially the esophagus, kidneys, and digestive tract—is replaced with scar tissue. This change causes the tissues to become stiff and the muscles to not work as well.

In the esophagus, this makes it:

• Easier for stomach juice to get into the esophagus. This happens because the valve between the esophagus and stomach (lower esophageal sphincter) does not close tightly.
• Harder to move stomach juices out of the esophagus. This happens because the squeezing motion of the esophagus (peristalsis) does not work as well as it should.

CREST syndrome is a limited type of scleroderma that can also affect the esophagus.