Fever is a common symptom in children. This symptom is particularly worrisome in children two to 36 months of age who have no identifiable source of infection. Previous guidelines for these children included empiric antibiotic therapy. These guidelines were developed before the establishment of routine immunization for Haemophilus influenzae infection in this age group. In addition, recent studies have not supported routine antibiotic therapy in children who have fever with no identifiable source for the prevention of serious bacterial infections. Bandyopadhyay and colleagues studied the rates of serious bacterial infections in children two to 36 months of age with fever and no identifiable source when antibiotics were reserved for use only in those with positive blood cultures.

The study was a retrospective review of febrile children two to 36 months of age who presented to the emergency department or urgent care center of an urban tertiary care children's hospital. During the study period, January 1, 1995, to July 31, 2000, researchers identified 9,241 cases. Patients eligible for the study included those who had a temperature of at least 39°C (102.2°F) and no source of infection. Children with fever who had been given antibiotics were excluded from the study. Standard care for children included blood cultures in those with a temperature of 41°C (105.8°F) or greater. Those with temperatures between 39.0°C (102.2°F) and 40.9°C (105.6°F) had blood cultures done at the discretion of the physician. Patients were followed with a telephone check within 24 to 48 hours. Those with positive blood cultures were identified, and appropriate interventions were taken at that time.

There were 2,641 children who met the inclusion criteria. Of those patients, 1,202 had blood cultures performed, and 37 (3 percent) had positive results. The most predominant organism found on blood cultures was Streptococcus pneumoniae. There were only two serious bacterial infections (0.08 percent) in the study group, and both patients recovered completely after appropriate intervention. Of the group that did not have blood cultures, 77 (5 percent) returned to the emergency department within one to two days with persistent fever. No identifiable source of fever was found in any of these patients at this visit, and in those who had blood cultures performed, all results were negative.

The authors conclude that with the use of routine immunization for H. influenzae, children two to 36 months of age who present with fever and no identifiable source do not require prophylactic antibiotic therapy. Antibiotic therapy can be reserved for those who have positive blood cultures. This strategy can be used without increasing the risk for serious bacterial infections.