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Aug 21, 2024 · Fever is an elevation in the body's temperature. It's not a disease but rather a sign or response to something occurring within the body, most commonly an infection. Noninfectious conditions or scenarios like inflammatory diseases or medication reactions can also cause a fever.
- Colleen Doherty, MD
- 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.
What are the most common causes of fever? A fever has many causes and can be a symptom of almost any illness. Common conditions that cause fever include: Bacterial infections. Viral infections such as influenza or COVID-19. Gastrointestinal (GI) infections. Urinary tract infections. Skin infections. You may also develop a fever due to:
What causes a fever? A fever is not an illness by itself. Rather it is a symptom that something is not right within the body. A fever does not tell you what is causing it, or even that a disease is present. It may be a bacterial or viral infection. Or, it could be a reaction from an allergy to food or medicine.
Apr 3, 2023 · This resetting of the hypothalamus is usually caused by small molecules called pyrogens in the blood. Causes of fever include: Hundreds of types of viruses, bacteria and parasites that cause many illnesses, such as upper respiratory infections, pneumonia, diarrhea and urinary tract infections
- hhp_info@health.harvard.edu
Nov 15, 2023 · Normal body temperatures are different for everyone, but they lie within the range of 97 to 99. A temperature of 100.4 or higher is considered a fever.
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Nov 12, 2024 · Being around infected blood or other body fluids. Complications. Viral hemorrhagic fevers can cause: Septic shock. Failure in more than one organ. Death. Prevention. It can be hard to prevent viral hemorrhagic fevers. If you live in, work in or travel to areas where these diseases are common, use protective barriers when working with blood or ...
