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Apr 25, 2024 · A fever occurs when the hypothalamus (a sensor area of our brain) increases our body temperature, usually to help “burn off” a viral or bacterial infection. A fever is often accompanied by other symptoms like feeling flushed, sweating, getting chills, muscle aches, and fatigue.
- Overview
- Symptoms
- Causes
- Complications
- Prevention
A fever is a temporary rise in body temperature. It's one part of an overall response from the body's immune system. A fever is usually caused by an infection.
For most children and adults, a fever may be uncomfortable. But it usually isn't a cause for concern. For infants, however, even a low fever may mean there's a serious infection.
Body temperatures vary slightly from person to person and at different times of day. The average temperature has traditionally been defined as 98.6 F (37 C). A temperature taken using a mouth thermometer (oral temperature) that's 100 F (37.8 C) or higher is generally considered to be a fever.
Depending on what's causing a fever, other fever signs and symptoms may include:
•Sweating
•Chills and shivering
•Headache
•Muscle aches
Typical body temperature is a balance of heat production and heat loss. An area in the brain called the hypothalamus (hi-poe-THAL-uh-muhs) — also known as your body's "thermostat" — monitors this balance. Even when you're healthy, your body temperature varies slightly throughout the day. It can be lower in the morning and higher in the late afternoon and evening.
When your immune system responds to disease, the hypothalamus can set your body temperature higher. This prompts complex processes that produce more heat and restrict heat loss. The shivering you might experience is one way the body produces heat. When you wrap up in a blanket because you feel chilled, you are helping your body retain heat.
Fevers below 104 F (40 C) associated with common viral infections, such as the flu, may help the immune system fight disease and are generally not harmful.
Fever or elevated body temperature might be caused by:
•A viral infection
•A bacterial infection
Children between the ages of 6 months and 5 years are at increased risk of a seizure that occurs during a fever (febrile seizure). About a third of the children who have one febrile seizure will have another one, most commonly within the next 12 months.
A febrile seizure may involve loss of consciousness, shaking of limbs on both sides of the body, eyes rolling back or body stiffness. Although alarming for parents, the vast majority of febrile seizures cause no lasting effects.
If a seizure occurs:
•Lay your child on the side or stomach on the floor or ground
•Remove any sharp objects that are near your child
•Loosen tight clothing
You may be able to prevent fevers by reducing exposure to infectious diseases. Here are some tips that can help:
•Get vaccinated as recommended for infectious diseases, such as influenza and COVID-19.
•Follow public health guidelines for wearing masks and social distancing.
•Wash your hands often and teach your children to do the same, especially before eating, after using the toilet, after spending time in a crowd or around someone who's sick, after petting animals, and during travel on public transportation.
•Show your children how to wash their hands thoroughly, covering both the front and back of each hand with soap and rinsing completely under running water.
•Carry hand sanitizer with you for times when you don't have access to soap and water.
May 22, 2023 · When to worry about fever. If you have a fever over 104°F (40°C), you should call your doctor. Seek medical help right away if you have a fever along with any of these symptoms: seizure; loss of consciousness; confusion; stiff neck; trouble breathing; severe pain anywhere in the body; swelling or inflammation of any part of the body
- 4 Blackfan Circle, 4th Floor, Boston, 02115, MA
- hhp_info@health.harvard.edu
- (877) 649-9457
- Unexplained weight loss. Losing weight without trying might sound like a dream come true, but in reality it can signal a health problem. If you don't have a body mass index of 30 or higher (obesity) and you've lost more than 10 pounds (4.5 kilograms), or more than 5 percent of your body weight, during the past six to 12 months consult your doctor.
- Persistent or high fever. A fever isn't necessarily a cause for alarm. Fever seems to play a key role in fighting infection. Persistent fever can signal a hidden infection, which could be anything from a urinary tract infection to tuberculosis.
- Shortness of breath. Shortness of breath could signal an underlying health problem. Very strenuous exercise, extreme temperatures, massive obesity and high altitude all can cause shortness of breath.
- Unexplained changes in bowel habits. What's considered normal for bowel movements varies widely. Consult your doctor if you notice unusual or unexplained changes in what's normal for you, such as
Feb 26, 2022 · A fever is a common sign of illness, but that's not necessarily a bad thing. In fact, fevers seem to play a key role in fighting infections. So should you treat a fever or let the fever run its course? Here's help making the call.
Sep 17, 2019 · A fever is usually a sign that your immune system is busy fighting an infection or other illness. In babies and toddlers even a slight fever may be a sign of a serious illness. In...
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Mar 5, 2019 · A fever of 101 degrees or higher is commonly associated with the flu. It’s uncomfortable, but it’s actually part of the body’s immune response. Fluids and anti-inflammatory medicines can help you stay comfortable.
