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Peptic ulcer
What causes peptic ulcer?
What is H. pylori?
Helicobacter pylori (H. pylori) is a type of bacteria. Researchers believe that H. pylori is responsible for the majority of peptic ulcers.
H. pylori infection is common in the United States: About 20 percent of people under 40 years old and half of those over 60 years have it. Most infected people, however, do not develop ulcers. Why H. pylori does not cause ulcers in every infected person is not known. Most likely, infection depends on characteristics of the infected person, the type of H. pylori, and other factors yet to be discovered.
Researchers are not certain how people contract H. pylori, but they think it may be through food or water.
Researchers have found H. pylori in the saliva of some infected people, so the bacteria may also spread through mouth-to-mouth contact such as kissing.
How does H. pylori cause a peptic ulcer?
H. pylori weakens the protective mucous coating of the stomach and duodenum, which allows acid to get through to the sensitive lining beneath. Both the acid and the bacteria irritate the lining and cause a sore, or ulcer.
H. pylori is able to survive in stomach acid because it secretes enzymes that neutralize the acid. This mechanism allows H. pylori to make its way to the "safe" area--the protective mucous lining. Once there, the bacterium's spiral shape helps it burrow through the lining.
What are the symptoms of an ulcer?
