Overview: Helicobacter pylori and extragastric disease

Isolation of the gastric spiral bacterium Helicobacter pylori totally reversed the false dogma that the stomach was sterile. In addition to its causal role in peptic ulceration, the newly identified bacterium has now been implicated in other gastric and even extragastric diseases, including chronic atrophic gastritis, gastric MALT lymphoma, gastric cancer, functional dyspepsia, idiopathic thrombocytopenic purpura (ITP), iron deficiency anemia, chronic urticaria, ischemic heart disease, and others. The majority of the reports are anecdotal, epidemiologic, or eradication studies, but there are also relevant in vitro studies. ITP represents one disease showing a strong link with H pylori infection. There are also accumulating data on the role of H pylori infection in iron deficiency anemia and ischemic heart disease. In summary, the association between H pylori infection and other extragut diseases is still controversial but worthy of further investigation.