For a 4-year-old, a fever is a temperature of 100.4°F (38°C) or higher. The exact reading depends on how you take it: oral (under the tongue), ear, forehead, or armpit thermometers each measure slightly differently. Most fevers in children this age are caused by common viral infections and resolve on their own within a few days.
How to Take an Accurate Temperature
By age 4, most children can hold a digital thermometer under their tongue long enough to get a reliable oral reading. This makes oral temperature the most practical option for preschoolers. If your child has been eating or drinking, wait 30 minutes before taking an oral reading, since hot or cold foods will skew the number.
You can also use a digital ear thermometer or a temporal artery (forehead) thermometer. Ear thermometers work well for quick checks, but earwax or a small, curved ear canal can throw off accuracy. Armpit readings are the least accurate method and tend to read lower than the true body temperature. If an armpit reading seems off, confirm it with an oral or ear thermometer.
What Causes Fever at This Age
Viral infections are by far the most common cause of fever in young children. Colds, flu, COVID-19, ear infections, throat infections, and tonsillitis are all typical culprits in the preschool years. These are the illnesses kids pick up from daycare, playgrounds, and siblings. Less commonly, bacterial infections like urinary tract infections or pneumonia can also drive a fever.
The fever itself isn’t the illness. It’s your child’s immune system ramping up to fight the infection. A higher number doesn’t necessarily mean a more serious illness. How your child looks and acts matters more than the number on the thermometer.
Keeping Your Child Comfortable
Treating a fever isn’t always necessary. If your child is playing, drinking fluids, and generally acting like themselves, you can let the fever run its course. The goal of treatment is comfort, not hitting a specific number.
If your child seems uncomfortable, irritable, or is having trouble sleeping, acetaminophen (Tylenol) or ibuprofen (Motrin) can help bring the temperature down. Dose by your child’s weight, not age, for the most accurate amount. Never give aspirin to children.
Hydration becomes especially important during a fever because your child loses more fluid than usual through sweating and faster breathing. Offer small, frequent sips of water throughout the day. If plain water is a hard sell, popsicles and diluted juice can work in a pinch. Avoid fizzy drinks, which can make things worse if your child also has an upset stomach. Watch for signs of dehydration: dark yellow urine, peeing less often than normal, a dry mouth, sunken eyes, or unusual drowsiness. Few or no tears when crying is another red flag.
Dress your child in light, breathable clothing. Bundling them up in blankets can trap heat and make the fever harder for their body to regulate. A comfortable room temperature is better than a cold room.
Febrile Seizures
Febrile seizures affect about 2% to 5% of children between 6 months and 5 years old, so a 4-year-old is still within the risk window. These seizures happen when a child’s temperature rises rapidly and can look alarming: the child may shake uncontrollably, become stiff, or lose consciousness for a short time. Most febrile seizures last less than a few minutes and don’t cause lasting harm, but a first-time seizure warrants an immediate call to emergency services.
Signs That Need Urgent Attention
Most fevers in 4-year-olds are harmless, but certain symptoms alongside a fever signal something more serious. Call emergency services if your child:
- Has a stiff neck or is bothered by light
- Develops a rash that doesn’t fade when you press a glass against it
- Is unusually drowsy or hard to wake
- Has difficulty breathing or is sucking their stomach in under their ribs
- Has blue, pale, or blotchy skin, lips, or tongue
- Has unusually cold hands and feet
- Is extremely agitated and won’t stop crying, or seems confused
- Is not responding like they normally would or has no interest in eating, drinking, or activities
A fever lasting more than three days, even without these symptoms, is also worth a call to your pediatrician. The same goes for a fever that goes away and comes back, which can suggest a secondary infection has developed.
When Your Child Can Go Back to School
CDC guidance recommends that children stay home until they’ve been fever-free for at least 24 hours without using fever-reducing medication. That means if your child’s temperature returns to normal only because they took Tylenol that morning, the clock hasn’t started yet. Wait until a full day passes with a normal temperature on its own before sending them back to school or daycare.