It depends on the specific pathogen that the child is infected with. Generally viral infections can get better on their own in 3-5 days with fever. In severe bacterial infections or when there is a combination of sepsis, the temperature may last about 5-10 days. If the child itself has Kawasaki disease and the fever is not treated with special treatment, such as propecia treatment or methylprednisolone, the temperature may last for more than 10 days or even longer. Tumor diseases, autoimmune diseases, and fevers can also last longer if they are not treated effectively. So there is no generalization about the duration of fever in children, it depends mainly on the specific disease.