In scleroderma, the immune system damages healthy tissue like collagen and replaces it with scar tissue, causing thickening and tightening of the skin as well as damage to other organs and systems. While the exact cause of the abnormal collagen production to begin is currently unknown, scleroderma is most likely caused by a combination of factors, including immune system problems, genetics and environmental triggers.
The same scarring and thickening that causes outward skin changes can also affect smooth muscle tissue in organs throughout the body. The salivary glands of the mouth often become scarred, leaving the person unable to produce saliva properly. As a result, they may experience severe dry mouth which causes difficulties in swallowing.
Scleroderma can affect the smooth muscle of the esophagus, damaging healthy tissue and replacing it with scar tissue.
Scleroderma causes strictures, or narrowing, of the esophagus and makes the muscle tissue weaker.
This can cause what doctors refer to as “motility disturbance” or trouble with food and liquid being able to travel down the esophagus. Scleroderma can also cause the sphincter muscle between the esophagus and the stomach (which helps prevent food from traveling backward into the esophagus after it has entered the stomach) to not close completely, causing gastroesophageal reflux disease (GERD), also called acid reflux or heartburn. Individuals with severe esophageal scleroderma can have a combination of GERD and gastroparesis (slow/delayed digestion), which can lead to the aspiration of stomach contents into the airway (throat). That can cause cough and respiratory issues, including pneumonia or worsening lung function.