Major causes of stomach problems in children include gastroenteritis, appendicitis and constipation, according to the American Academy of Family Physicians. Viruses such as Norwalk virus and enterovirus are usual causes of gastroenteritis. E. coli, salmonella and shigella bacteria and parasites such as giardia can also cause gastroenteritis.
The symptoms of gastroenteritis in children are diarrhea, fever, nausea and vomiting, states the American Academy of Family Physicians. The danger of gastroenteritis is dehydration due to vomiting and diarrhea.
Appendicitis is the inflammation of the appendix, says Cleveland Clinic. When a child has appendicitis, he experiences pain that starts around the navel then moves toward the right side of his belly. Nausea and vomiting accompany the pain, as does loss of appetite, diarrhea after a few days, painful urination or increased urination, and a low-grade fever. His belly is also tender and rigid.
When a child has constipation, he has fewer bowel movements than usual, and the bowel movements he does have are hard and dry, says Mayo Clinic. Many things can cause constipation. For example, a child may not go to the bathroom because he does not want to take a break from an activity, and when he finally does, it hurts. Also, he may have a diet low in fiber or have a sudden change in his regular routine.