Which condition is characterized by backflow of acidic gastric contents into the esophagus?

Gastroesophageal reflux disease (GERD) is characterized by the backflow of acidic gastric contents into the esophagus. This condition occurs when the lower esophageal sphincter (LES) fails to close properly, allowing stomach acid to flow back into the esophagus. The result is irritation and inflammation of the esophageal lining, which can lead to symptoms such as heartburn, regurgitation, chest pain, and difficulty swallowing.

In contrast, gastritis refers to inflammation of the stomach lining, while esophageal varices involve swollen veins in the esophagus often due to liver disease or portal hypertension. Peptic ulcer disease involves sores that develop on the lining of the stomach or the upper part of the small intestine, generally caused by infection with H. pylori or long-term use of nonsteroidal anti-inflammatory drugs (NSAIDs). These conditions do not specifically involve the reflux of gastric contents into the esophagus, making GERD the most appropriate answer for backflow of acidic gastric contents.