Fever, which is defined as a core body temperature ≥ 100.4°F or 38°C, is one of the most common causes of pediatric health care visits. Fever is the body's normal response to an underlying infection and/or inflammatory process (e.g., rheumatologic conditions, malignancy). Following the introduction of routine childhood and , acute pediatric fevers in children aged > 60 days are most commonly caused by self-limited viral infections. Diagnostic studies are not usually required but should be performed if any are present to identify serious bacterial infections. Children who have require additional evaluation, even if they appear well on examination, and may require antibiotics and hospital admission. Supportive care is the mainstay of treatment for children with fever and should include adequate hydration and antipyretics for discomfort. Education for caregivers is important to reduce anxiety over fever in children and help manage future episodes at home.
Fever is the presenting concern in:
- ∼ 30% of pediatric primary care visits 
- 15% of emergency room visits in children < 15 years of age 
Epidemiological data refers to the US, unless otherwise specified.
Infectious causes of pediatric fever 
- Common infectious conditions include:
- Less common causes include: 
Noninfectious causes of pediatric fever 
Common findings 
- Physiological adaptations to fever, e.g.:
- Associated behavioral changes, e.g.:
- Decreased activity
- Fussiness or irritability
- Clinical features of the underlying condition (see “Etiology of pediatric fever”)
Rectal temperature is the best indicator of core temperature. 
Red flags for pediatric fever 
- Ill-appearance 
- Signs of respiratory distress
- Petechial rash or other 
- Prolonged capillary refill time (> 3 seconds)
- Altered mental status including reduced arousability
- Seizures 
Febrile seizures are common, affecting 2–5% of young children. Simple febrile seizures in a well-appearing child are not concerning, but all other febrile seizures should prompt consideration of and/or neuroimaging. 
- In well-appearing children, a diagnosis can often be made clinically after a thorough history and examination.
- When required, diagnostics for fever are usually evaluations for the suspected etiology.
- In fever of unknown source, consider more extensive diagnostic studies, particularly in children < 3 years of age.
- In children with empiric antibiotic treatment without waiting for diagnostic studies. or , give
Initiate treatment without awaiting the results of diagnostic studies in children with suspected serious bacterial infections.
Evaluations for suspected etiology
- Based on the clinical examination, evaluate for suspected conditions, e.g.:
- See also “Etiology of pediatric fever.”
Unclear source 
Initial investigations for acute fever focus on infectious causes; if test results are negative consider .
Children with red flags for pediatric fever
- Blood tests
- Urine studies: urinalysis with reflex urine culture
- CSF studies: if neurologic symptoms or signs of meningitis are present
When possible, obtain cultures before initiating empiric antibiotic therapy.
- Evaluate for red flags for pediatric fever and if present:
- Provide .
- Initiate immediate broad-spectrum empiric antibiotics (see “Treatment”).
- Perform .
- For well-appearing children with risk factors for life-threatening pediatric infections, provide additional management. 
- Underimmunized children: Evaluate for .
- Children with indwelling devices: See “Management of device-related infections.”
- Children with immunosuppression
- Consult relevant specialty.
- Follow local protocols where available, e.g., for .
- Children with sickle cell disease: Consult hematology and start .
- Children with prematurity or significant congenital abnormalities: Consult pediatrics.
- Currently hospitalized children: Consult infectious disease/microbiology for advice on the .
In children with , do not delay treatment for diagnostic studies.
- Treat the underlying cause.
- Give empiric antibiotics to children with red flags for pediatric fever and/or risk factors for life-threatening pediatric infections.
- Tailor to the suspected source, e.g.:
- If the source is unclear, give ceftriaxone. 
- Tailor to the suspected source, e.g.:
Supportive care for pediatric fever 
- Ensure adequate fluid intake via oral or IV fluids.
- Maintain a comfortable room temperature and dress the child in light clothing.
- If fever is bothersome to the child, consider:
- Provide anticipatory guidance for pediatric fever.
When the child needs an assessment for fever
Indications for immediate evaluation 
Children with any of the following should be evaluated immediately, typically in an emergency department setting.
- Hyperpyrexia, i.e., temperature ≥ 106 °F (≥ 41 °C), or repeated temperatures > 104 °F (≥ 40 °C) 
Indications for outpatient evaluation
An outpatient evaluation is recommended for children with:
- Signs of bacterial infection
- Infants and children 2–36 months with unexplained fever (i.e., no localizing symptoms) 
- Rapid testing during viral outbreaks (e.g., influenza, COVID-19) 
- Prolonged fever, i.e.: 
Home management of fever 
The following information pertains to otherwise healthy infants and children > 60 days old.
- If viral URTI symptoms are present, recommend:
- Provide reassurance to decrease caregiver anxiety about fever (fever phobia), e.g.:
- If antipyretic use is indicated, advise caregivers on ways to minimize dosing errors and adverse effects.
- Stay home until afebrile, without the use of antipyretics, for at least 24 hours.