When a Fever Is Not Just a Fever: What Every Parent Should Know

Fevers are one of the most common reasons parents worry about their kids. Fevers are usually harmless, but there are times when a high temperature suggests something more serious. Our pediatric experts explain the difference between a common fever and when it is something more that requires medical attention. 

What causes a fever? 

A fever is a rise of body temperature 100.5°F or higher. Digital thermometers (rectal, oral or axillary) are the best way of taking your child's temperature and are sold at most drugstores.

Fever is a symptom; it is not a disease or sickness. It is your child's natural response to an illness. When the body detects a virus or bacteria, it raises its temperature to kill those germs. 

The most common cause of a fever is a viral infections like colds and flu. These typically go away on their own within a few days as the body fights off the infection. Fevers are good as they fight infections. Fevers are bad as they make you feel lousy. Treating a fever too aggressively might interfere with this natural defense mechanism. However, knowing when to relax and when to act is important for every parent.   

Age-Specific Fever Guidelines: When to Call the Doctor 

The importance of a fever can depend on your child's age. Newborns and young infants have not had time to develop strong immune systems and can get serious infections without showing any obvious signs, making age-based guidelines critically important: 

• For infants under 2 months: Any rectal temperature of 100.5°F or higher requires immediate medical attention. Do not wait, go to the emergency department because even minor infections in babies this young can quickly become serious. 

• For infants 2 to 6 months: Contact your pediatrician if your baby has a fever, or if they have a lower fever but appear very tired, irritable or unusually fussy. 

• For children 6 to 24 months: Call your doctor if your child’s temperature is above 102°F and lasts more than 24 hours, or any fever for more than 3 days.  

• For children over 3 years: While older children can deal with fevers better, you should contact your pediatrician if the temperature is higher than 104°F, if it lasts longer than three days or if your child has concerning symptoms regardless of the fever's height. 

How do you treat a fever? 

In young children (0-36 months), treatment will be determined by a medical team. For older children, initial treatment is aimed at increasing fluids and getting plenty of rest. The main goal is to make your child more comfortable. You treat your child, not the number. Other treatments include a sponge bath with tepid or slightly warm (not cold) water, or a dose of acetaminophen (Tylenol) or ibuprofen (Motrin) based on their weight or age. 

Fevers do not usually need to be treated unless your child is uncomfortable or has a history of febrile seizures. Fever becomes worrisome if the child is not responding normally, has seizures, has an underlying chronic condition or has a fever of above 104 degrees Fahrenheit that lasts for longer than three days. 

When to Seek Immediate Care 

Sometimes the fever itself is not the main concern—it's the accompanying symptoms that signal a medical emergency. Go to the emergency room immediately if your child experiences any of the following alongside a fever: 

• Difficulty or hard time breathing, breathing fast or increased work to breath.
• Severe headache or stiff neck that prevents normal neck movement
• Repeated vomiting or diarrhea can lead to dehydration (signs include no tears when crying, decreased urination, less than 3 diapers a day, dry mouth, or sunken eyes)
• New skin rash, especially purple or blood-colored spots
• Seizures or convulsions
• Extreme sleepiness or hard waking up
• Confusion, unusual behavior, not acting like themselves
• Severe abdominal pain, belly pain with walking, unable to stand up straight from pain
• Blue lips, tongue, or nails

If your child looks or acts very sick or you notice they're getting worse rather than better, seek medical care immediately, even if their temperature isn't particularly high. 

When Fever Signals Kawasaki Disease 

A condition that parents should be aware of is Kawasaki disease, a rare but serious illness that begins with a persistent fever. This disease causes inflammation of blood vessels throughout the body and is the #1 cause of acquired or new heart disease in children in developed countries. 

Kawasaki disease primarily affects children under 5 years old, particularly those of Japanese and Korean descent, though it can occur in any child. The classic sign is a high fever, often between 101°F and 104°F, that lasts for five days or longer and doesn't respond well to fever-reducing medications. 

Beyond the prolonged fever, parents should watch for these additional warning signs: 

• A rash on the main part of the body or in the genital area
• Swollen lymph nodes in the neck, usually on one side
• Bloodshot eyes (red or pink) without discharge or tearing
• Bright red, cracked lips and a "strawberry tongue" (red with enlarged bumps)
• Swelling and redness of the hands and feet sometimes with redness, followed by peeling skin around the nails
• Extreme irritability and fussiness that's unusual for your child

Some children may also experience joint pain, belly pain, vomiting or diarrhea. Not every child displays all these symptoms. 

The critical concern with Kawasaki disease is its potential to damage the coronary arteries that supply blood to the heart. However, when diagnosed early and treated, typically within 10 days of symptoms starting, most children recover fully without long-term complications.  

If your child has a fever lasting five or more days, especially if they have any of the symptoms listed above, contact your pediatrician immediately or seek emergency care. Early recognition and treatment of Kawasaki disease can prevent serious heart complications. 

Learn more about Kawasaki disease here.

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