Fever in children is one of the most – and anxiety-inducing – concerns for parents and caregivers. While many pediatric fevers are harmless, some can signal more serious underlying conditions. A systematic approach to evaluating pediatric fever can help ensure that serious conditions are not overlooked. One effective method is to categorize potential diagnoses into three main buckets: Common Infections, Serious Infections, and Non-Infectious Causes.
Common Infections
The majority of pediatric fevers fall into this category. These infections are the ones you see most often in clinical practice and are generally self-limiting, though they can still cause significant discomfort and distress.
- Viral Upper Respiratory Infections (URIs): This group includes common viruses like influenza, COVID-19, and rhinovirus. Expect symptoms like a runny nose, cough, and sore throat.
- RSV/Bronchiolitis: Respiratory syncytial virus (RSV) is a leading cause of bronchiolitis, particularly in infants. Look for wheezing, coughing, and difficulty breathing.
- Hand-Foot-Mouth Disease: Caused by the coxsackievirus, this illness is characterized by fever, mouth sores, and a rash on the hands and feet.
- Croup: This viral infection leads to the distinctive barking “seal-like” cough and hoarseness, often worse at night.
- Urinary Tract Infections (UTIs): The most common occult bacterial infection in children, especially females and uncircumcised males aged 3-24 months.
- Acute Otitis Media: This is a common cause of fever, particularly in younger children. It is often accompanied by ear pain and fever.
- Strep Pharyngitis: Caused by group A Streptococcus, this bacterial throat infection is more common in school-aged children and can present with fever, sore throat, and swollen lymph nodes.
- Viral gastroenteritis: This GI infection can often present with fever, nausea, vomiting, and diarrhea.
- Pneumonia: An infection of the lungs that can be caused by viruses or bacteria, often presenting with fever, cough, and difficulty breathing.
Serious Infections
While less common, serious infections require prompt recognition and treatment to prevent severe complications. These conditions can be life-threatening if not addressed quickly.
- Invasive Bacterial Infections (IBI): Conditions like meningitis and bacteremia fall here. Patients with IBI often appear lethargic and need a full sepsis workup in the ED.
- Herpes Simplex Virus (HSV): Particularly concerning in neonates, HSV can lead to severe infections, including encephalitis.
- Abdominal Infections: Conditions like appendicitis can present with fever and abdominal pain.
- Bacterial/Septic Arthritis: An infection of the joints that can cause severe pain, swelling, and fever – often signaled by a new limp.
- Osteomyelitis: A bacterial infection of the bone, often presenting with localized pain, fever, and sometimes swelling over the affected area.
- Vaccine-Preventable Infections (if unvaccinated): In children who are not up-to-date on their vaccinations, diseases like measles, whooping cough, diphtheria, and epiglottitis can cause high fever and other severe symptoms.
Non-Infectious Causes
Not all fevers in children are due to infections. It’s important to consider non-infectious causes, especially when common and serious infections have been ruled out.
- Kawasaki Disease: A condition that causes inflammation of blood vessels and can lead to heart complications. It often presents with prolonged fever, rash, red eyes, a strawberry tongue, and swollen hands and feet.
- Central Nervous System (CNS) Dysfunction: Conditions affecting the brain and spinal cord can present with fever.
- Malignancy: Certain cancers, like leukemia or lymphoma, can cause prolonged, unexplained fever.
- Inflammatory Bowel Disease (IBD): Chronic inflammation of the gastrointestinal tract, including Crohn's disease and ulcerative colitis, can cause fever, abdominal pain, and diarrhea.
- Juvenile Idiopathic Arthritis (JIA): A type of arthritis in children that can cause joint pain, swelling, and fever.
Conclusion
Approaching pediatric fever with these three buckets of diagnoses – common infections, serious infections, and non-infectious causes – allows for a thorough and organized evaluation. Many factors, such as the child’s age, past medical history, vaccination status, HPI, and physical exam, can make each differential more or less likely. For a more in-depth look at pediatric fever, check out this chapter in the NP Clinical Resource Guide.