Gastritis

Gastritis is inflammation of the gastric mucosa, the layer that lines the inside of the stomach. Being inflamed means that layer is in the middle of a defensive reaction, like the skin around a cut that turns red and swollen.

The most frequent cause is a bacterium, Helicobacter pylori, that takes up residence in the stomach. It is not the only cause: in autoimmune gastritis, the immune system, which is supposed to protect us, mistakenly attacks healthy cells in that same lining.

Most people with gastritis feel nothing. When symptoms do occur, they can include pain or discomfort in the upper abdomen. Gastritis caused by Helicobacter pylori also raises the risk of ulcers, which are sores in the lining and can bleed, as well as the risk of stomach cancer. A higher risk does not mean an ulcer or cancer will develop; it means the chance is higher than in someone without this kind of gastritis.

And not all damage to the mucosa is gastritis: when prolonged exposure to nonsteroidal anti-inflammatory drugs (a type of pain medication), alcohol, or bile injures the lining with little or no inflammation, that is called gastropathy.