Helicobacter pylori (H. pylori) infection is reported to be associated with many 
extragastrointestinal manifestations, such as hematological diseases [idiopathic 
thrombocytopenic purpura (ITP) and unexplained iron deficiency anemia (IDA)], 
cardiovascular diseases (ischemic heart diseases), neurological disorders 
(stroke, Parkinson's disease, Alzheimer's disease), obesity and skin disorders. 
Among these, the best evidence so far is in ITP and unexplained IDA, with 
high-quality studies showing the improvement of IDA and ITP after H. pylori 
eradication. The evidence of its association with coronary artery disease is 
weak and many of the results may be erroneous. The role of H. pylori infection 
in affecting serum leptin and ghrelin levels has attracted a lot of attention 
recently and available data to date have been conflicting. There have also been 
many uncontrolled, small sample studies suggesting an association between H. 
pylori infection and neurological disorders or chronic urticaria. However, more 
studies are required to clarify such proposed causal links.