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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 ...
- 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.
A fever is when your body temperature rises higher than normal. A fever itself isn’t an illness. Rather, it’s a symptom of a wide range of health conditions. When your body temperature rises a few degrees above normal, it can be a sign that your immune system has been activated, often to fight an infection. It can also be a side effect of ...
Apr 3, 2023 · High fever can lead to symptoms of mental dysfunction, such as confusion, excessive sleepiness, irritability and convulsions (seizures). Convulsions triggered by fever (febrile seizures) are common among children younger than 5 years. These seizures usually occur at the beginning of an illness when temperature rises rapidly.
- hhp_info@health.harvard.edu
If no localizing findings are present, healthy people with acute fever and only nonspecific findings (eg, malaise, generalized aches) most likely have a self-limited viral illness, unless a history of exposure to infected contacts (including a new, unprotected sexual contact), to disease vectors, or in an endemic area (including recent travel) suggests otherwise.
- Larry M. Bush
Nov 15, 2023 · A fever is a sign of an illness or infection. When you have one, you may notice these symptoms: ... it could be more unusual like a connective tissue disorder (diseases that affect things like ...
People also ask
Is a fever a symptom of an illness?
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An infectious cause is highly likely in adults with a fever that lasts 4 days or less (called an acute fever). An acute fever in people with cancer or a known inflammatory disorder also is most likely to have an infectious cause. In healthy people, an acute fever is unlikely to be the first sign of a chronic illness.
