The presence of systemic symptoms varied considerably among different countries. A recent meta-analysis of 29 studies, mainly from China, demonstrated that anorexia was present in 21%, nausea and/or vomiting in 7%, diarrhea in 9%, and abdominal pain in 3% of the cases, respectively. However, in a study from the United States, the systemic symptoms of anorexia (34.8%), diarrhea (33.7%), and nausea (26.4%) were found to be more common [14].