It may be a side effect of drugs, or a warning signal of illness at other parts of the body.
Children suffering from febrile illnesses often complain of some degree of gastrointestinal upset.
If in doubt, consult your doctor. The condition is usually self-limiting if managed properly. Mismanagement may lead to dehydration as a result of fluid and electrolyte loss. Early signs are thirst, dry lips and dry tongue. If left untreated, urine darkens and volume decreases, eyeballs become sunken and skin loses elasticity.