Sometimes GERD can cause serious complications. Inflammation of the esophagus from stomach acid causes bleeding or ulcers. In addition, scars from tissue damage can narrow the esophagus and make swallowing difficult. Some people develop Barrett's esophagus, where cells in the esophageal lining take on an abnormal shape and color, and which over time can lead to cancer. Also, studies have shown that asthma, chronic cough, and pulmonary fibrosis may be aggravated or even caused by GERD.