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Fever is also known as hyperthermia, pyrexia, or elevated temperature. It describes a body temperature that’s higher than normal. Fever can affect children and adults. A short-term increase in body temperature can help your body fight off illness. However, a severe fever can be a symptom of a serious condition that requires immediate medical attention.
Recognizing a fever can enable you to get treatment and proper monitoring for it. Normal body temperature is typically around 98.6°F, or 37°C. However, the normal body temperature for each person can vary slightly. Normal body temperature may also fluctuate depending on the time of day. It tends to be lower in the morning and higher in the late afternoon and evening. Other factors, such as your menstrual cycle or intense exercise, can also affect body temperature.
To check you or your child’s temperature, you can use an oral, rectal, or axillary thermometer.
An oral thermometer should be placed under the tongue for three minutes.
You may also use an oral thermometer for an axillary, or armpit, reading. Simply place the thermometer in the armpit and cross your arms or your child’s arms over the chest. Wait four to five minutes before removing the thermometer.
A rectal thermometer may be used for measuring body temperature in infants. To do this, place a small amount of petroleum jelly on the bulb. Then, lay your baby on their stomach and gently insert the thermometer about 1 inch into your baby’s rectum. Hold the bulb and your baby still for at least three minutes.
In general, a baby has a fever when their body temperature exceeds 100.4°F, or 38°C. A child has a fever when their temperature exceeds 99.5°F, or 37.5°C. An adult has a fever when their temperature exceeds 99 to 99.5°F, or 37.2 to 37.5°C.
Fever occurs when a part of the brain called the hypothalamus shifts the set point of your normal body temperature upward. When this happens, you may feel chilled and add layers of clothing or you may start shivering to generate more body heat. This eventually results in a higher body temperature.
There are numerous different conditions that can trigger fevers. Some possible causes include:
Depending on the cause of the fever, additional symptoms may include:
Care for a fever depends on its severity. A low-grade fever with no other symptoms doesn’t typically require medical treatment. Drinking fluids and resting in bed are usually enough to fight off a fever.
When a fever is accompanied by mild symptoms, such as general discomfort or dehydration, it can be helpful to treat elevated body temperature by:
A mild fever can typically be treated at home. In some cases, however, a fever can be a symptom of a serious medical condition that requires prompt treatment.
You should take your infant to a doctor if they’re:
You should take your child to see a doctor if they:
You should call your doctor if you:
You or your child should also see a doctor as soon as possible if a fever is accompanied by any of the following symptoms:
Your doctor will probably perform a physical examination and medical tests. This will help them determine the cause of the fever and an effective course of treatment.
Go to the nearest emergency room or call 911 if you or your child is experiencing any of the following:
Limiting exposure to infectious agents is one of the best ways to prevent a fever. Infectious agents often cause body temperature to rise. Here are some tips that can help reduce your exposure:
Written by: Krista O'Connell
Medically reviewed on: Feb 29, 2016: Deborah Weatherspoon, Ph.D, MSN, RN, CRNA
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