Esophagitis is inflammation of the lining of the esophagus, the muscular tube that connects the pharynx (throat) to the stomach. In children, it is usually the result of gastroesophageal reflux disease (GERD), eosinophilic esophagitis, infection, or ingestion of corrosive substances (such as cleaning products or battery acid). Over time, esophagitis can lead to dysmotility, narrowing of the esophagus, or precancerous changes of the esophagus (Barrett's esophagus).