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High fever in a child
Medical expert of the article
Last reviewed: 04.07.2025
A high temperature in a child is a normal and healthy response to infection and other illnesses, both minor and serious. Fever helps your child's body fight infection. Fever is a symptom, not a disease. Most of the time, fever in children means they have a minor illness. But if your child has a high temperature, other, additional symptoms can help you determine how serious their illness is.
Causes of high temperature
Viral infections such as colds and flu, as well as bacterial infections such as urinary tract infections or pneumonia, often cause high fever.
Traveling or walking with a child in unfamiliar places or traveling to a country with a different climate can lead to serious illnesses. A child’s fever that occurs after traveling to other countries should be assessed by a doctor.
A child may have a fever and respiratory symptoms that are difficult to assess during flu season. A child with a fever of 101.5F (38.9C) or higher for 3 to 4 days may have flu-like symptoms.
A child has a recurrent fever when they have 3 or more fevers in a 6-month period, with at least a week between each fever. Each new viral infection can cause a fever in a child. It may seem like the child is continuing to have a fever, but if there is a 2-day gap between the high temperature and the temperature going down, it is a recurrent fever. If your child has frequent or intermittent fevers, it may be a symptom of a more serious problem. The best advice on this is provided by your child's doctor.
Elevated temperature
A temperature of up to 38.9C can be beneficial for a child because it helps the body fight infection. The healthiest children and adults can tolerate temperatures higher than 39.4C or even 40C without problems – albeit for short periods of time. Children tend to tolerate high temperatures better than adults.
The height of the temperature may not give an adult an idea of how serious a child's illness is. A minor illness, such as a cold, may cause a child to have a high fever, while a very serious infection may cause a low fever. It is important to look for and evaluate other symptoms of illness in a child, along with the temperature.
So, if you are unable to measure the temperature with a thermometer, you need to look for other symptoms of illness. A high fever without other symptoms that lasts for 3 to 4 days, comes and goes, and gradually decreases over time is usually not a cause for concern. If a child has a high fever, he or she may feel tired, weak, and have lost their appetite. A high fever is uncomfortable, but it rarely causes serious health problems.
Symptoms of fever in a child
Symptoms of fever in a child may be obvious or almost imperceptible. The younger the child, the more difficult it is to recognize the symptoms of high fever.
This is how children under one year react to high temperatures
- The child is irritable
- The child is too weak and quiet
- The baby is too hot
- The baby has a decreased appetite
- The baby cries often
- Breathes quickly
- The child sleeps poorly
Children who can already speak complain about:
- temperature changes while other people in the same room or environment feel comfortable,
- body aches,
- headache,
- difficulty sleeping or, on the contrary, unable to wake up
- poor appetite.
Who to contact?
How to measure a child's temperature?
There are several ways to measure a child's temperature. Children under 4 years old can measure their temperature under their armpits - a thermometer is inserted there. There is an oral method of measuring temperature, when the thermometer is placed in the mouth. But there is a great danger that the child will bite off the tip of the thermometer, and then mercury will enter his body. Therefore, when measuring temperature, it is worth considering the child's age.
Normal body temperature
Most people have an average body temperature of about 37C, measured orally (by placing the thermometer under the tongue) or under the armpit. The temperature may be 36.3C in the morning or 37.6C at the end of the day. The temperature may rise when you exercise, wear too many clothes, take a hot bath, or are in a hot environment. The same applies to a child. His temperature may rise slightly when he is exposed to different temperature conditions. This is normal.
Treating high fever in a child
In most cases, the cause of the illness that caused your child's fever will become clear within a few days. You can usually treat the illness at home if there are no other serious health problems. Make sure your child eats and drinks enough food and fluids when they have a fever. This will help the body fight the illness that has arisen.
Only a doctor can prescribe specific treatment for a child’s high temperature; self-medication is inappropriate here.
A high temperature in a child should certainly not be ignored, even if it is episodic and soon passes.