Fever or chills in teens and adults: Overview
A fever is the body's normal and healthy reaction to infection and other illnesses, both minor and serious. It helps the body fight infection. A fever is a symptom, not a disease. In most cases, having a fever means that you have a minor illness. When you have a fever, your other symptoms will help you know how serious your illness is.
Temperatures in this topic are oral temperatures. Oral temperatures are usually taken in older children and adults.
Normal body temperature
Most people have an average body temperature of about 98.6°F (37°C) , measured orally (under the tongue). Your temperature may be as low as 97.4°F (36°C) in the morning or as high as 99.6°F (38°C) in the late afternoon. Your temperature may go up when you exercise, wear too many clothes, take a hot bath, or are exposed to hot weather.
Fever temperatures
A fever is a high body temperature. A temperature of up to 102°F (39°C) can be helpful because it helps the body fight infection. Most healthy children and adults can tolerate a fever as high as 103°F (39°C) to 104°F (40°C) for short periods of time without problems. Children tend to have higher fevers than adults.
The degree of fever may not show how serious the illness is. With a minor illness, such as a cold, you may have a fever. But a very serious infection may cause little or no fever. It's important to look for and evaluate other symptoms along with the fever.
If you can't measure your temperature with a thermometer, you need to look for other symptoms of illness. A fever without other symptoms that lasts 3 to 4 days, comes and goes, and gradually reduces over time usually isn't a cause for concern. When you have a fever, you may feel tired, lack energy, and not eat as much as usual. High fevers aren't comfortable. But they rarely cause serious problems.
An oral temperature taken after you smoke or you drink a hot fluid may give you a false high temperature reading. After you drink or eat cold foods or fluids, your oral temperature may be falsely low.
Causes of fever
Viral infections, such as colds and flu, and bacterial infections, such as a urinary tract infection or pneumonia, often cause a fever.
Travel outside your native country can expose you to other diseases. Fevers that start after travel in other countries need to be checked by your doctor.
Fever and respiratory symptoms are hard to evaluate during the flu season. A fever of 102°F (39°C) or higher for 3 to 4 days is common with the flu.
Recurrent fevers are ones that occur 3 or more times within 6 months and are at least 7 days apart. Each new viral infection may cause a fever. It may seem that a fever is ongoing. But if 48 hours pass between fevers, then the fever is recurring. If you have frequent or recurrent fevers, they may be a symptom of a more serious problem. Talk to your doctor about your fevers.
Treating a fever
In most cases, the illness that caused the fever will clear up in a few days. You usually can treat the fever at home if you are in good health and don't have any medical problems or significant symptoms with the fever. Make sure that you are taking enough foods and fluids and urinating in normal amounts.
Low body temperature
If a low body temperature is your only symptom, it's not something to worry about. If a low body temperature occurs with other symptoms, such as chills, shaking, breathing problems, or confusion, then this may be a sign of more serious illness.
Low body temperature may occur from cold exposure, shock, alcohol or drug use, or certain metabolic disorders, such as diabetes or hypothyroidism. A low body temperature may also occur with an infection. This is most likely in newborns, older adults, and people who are frail. An overwhelming infection, such as sepsis, may also cause an abnormally low body temperature.
Shaking chills (rigors)
Shaking chills (rigors) are the body's reaction to a severe infection or the release of organisms, such as viruses or bacteria, into the bloodstream. These chills often occur with a high fever and sometimes make teeth chatter or, when severe, can cause uncontrollable shaking that can make a bed vibrate.
Caring for a child who has a fever or chills
It can be hard to know if you should call your doctor when your child (age 1 to 11 years) has a fever, especially during the cold and flu season. The degree of the fever may not be related to the seriousness of the illness. The way your child looks and acts is a better guide than the thermometer. Most children will be less active when they have a fever.
If your child is comfortable and alert, is eating well, is drinking enough fluids, is urinating normal amounts, and seems to be improving, home treatment without medicine is all that's needed for a fever. Dress your child lightly. Don't wrap him or her in blankets. Dressing lightly will help your child's body cool down.
Try these home treatment measures to make sure that your child is drinking enough fluids and doesn't get dehydrated while he or she has a fever.
- Don't let your child get dehydrated.
- Make sure that your child drinks often. Frequent, small amounts work best.
- Allow your child to drink as much fluid as he or she wants. Encourage your child to drink extra fluids or suck on flavored ice pops, such as Popsicles. Don't give your child fruit juice or soda pop. They contain too much sugar and not enough of the essential minerals (electrolytes) that are being lost. Diet soda pop lacks calories that your child needs.
- Cereal mixed with milk or water may also be used to replace lost fluids.
- If your child still isn't getting enough fluids, you can try an oral rehydration solution (ORS).
- Keep your child comfortable.
Lowering your child's temperature is important when the fever is causing discomfort. If your child is uncomfortable:
- Try giving your child a sponge bath with lukewarm water. Don't use cold water, ice, or rubbing alcohol.
- Encourage quiet activities.
- Watch for signs of dehydration. These include your child being thirstier than usual and having less urine than usual.
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