High temperatures in children can indicate that an infection of the skin, throat, lung, ear, bladder or kidney exists, explains WebMD. Some children run a fever after vaccinations or as a side effect of medications. Conditions that cause inflammation and cancer can also produce fevers in children as can a common cold or gastroenteritis.
Additional ailments that can cause high temperatures in children include hormone disorders; autoimmune diseases, such as inflammatory bowel disease, lupus or rheumatoid arthritis; and blood clots, according to WebMD. Children exposed to illegal drugs, such as cocaine and amphetamines, may also experience fevers. Doctors diagnose some children with a "fever of unknown origin" that is due to a condition such as a chronic infection or connective tissue disorder.
Children with fevers commonly experience a headache, muscle aches, a general feeling of weakness, a loss of appetite and dehydration, according to Mayo Clinic. Some children may also begin sweating or shivering. High fevers that exceed 103 degrees Fahrenheit may produce confusion, irritability, convulsions or hallucinations in children.
If children with fevers vomit repeatedly, appear to be listless and complain of a stomach ache or severe headache, they need medical evaluation, advises Mayo Clinic. Children with fevers that last longer than three days also need to see a doctor.