For centuries, fever has been associated with illness. As many as 30% of all patients seen by primary care physicians and more than 5 million emergency department visits each year[1] have fever as their principal complaint, making it one of the most common reasons children are taken to a physician. Add to this fact the multitude of telephone calls about fever that are received day and night by health care providers, and, it becomes evident that the proper evaluation and management of fever is a basic and necessary skill for everyone caring for children.

Even though clinicians have long dealt with this common clinical sign, its mechanism, meaning, and management have remained sufficiently unclear and controversial that research on these matters continues. Although advances in neurochemistry and neurophysiology have improved the understanding of the pathophysiology of fever (see Chapter 53, Physiology and Management of Fever), clinical investigators continue to search for practical knowledge that will enhance the care of the febrile patient. Availability of such information can simplify the challenging role of the physician, who must evaluate a child quickly and effectively, arrive at a diagnosis, institute appropriate therapy, and both educate and support the parents and child during the entire process. The extent to which health care practitioners accomplish these goals depends on their knowledge of the mechanisms of disease, the various clinical manifestations of disease, and their awareness of the social context in which the disease occurs.