What Is a Fever?
![Fever is often defined as a core (rectal) body temperature of 100.4° F (38.0° C) or greater in adults and 99°F (37.2°C) (armpit) or 100.4°F (38°C) (rectal) in babies under one year. A fever usually isn't a concern unless it is 103° F (39.4° C) or higher.](https://images.medicinenet.com/images/article/main_image/women-with-fever.jpg?output-quality=75)
A fever is a higher-than-normal body temperature. A fever is not an illness in itself, but a sign the body is fighting an infection.
Is A Temperature of 96.8 Normal?
The standard of 98.6° F (37° C) as a normal average oral temperature was determined in the 1800s but recent studies have shown the average body temperature has dropped to 97.5° F (36.4° C). This is believed to be due to more accurate thermometers, lower rates of infection, and lower metabolic rates because people now weigh more on average than they did in the 1800s.
What Are Symptoms of Fever?
Fever is often defined as a core (rectal) body temperature of 100.4° F (38.0° C) or greater in adults and 99°F (37.2°C) (armpit) or 100.4°F (38°C) (rectal) in babies under one year. A fever usually isn't a concern unless it is 103° F (39.4° C) or higher.
Additional symptoms that may accompany a fever depend on the cause and may include:
- Sweating
- Flushing
- Chills and shivering
- Headache
- Weakness
- Muscle aches and pains
- Loss of appetite
- Dehydration
- Loss of appetite
- Irritability
- Glassy eyes
- Febrile seizures in children between the ages of 6 months and 5 years
Contact your doctor if you have a fever and:
- It is 103° F (39.4° C) or higher
- It lasts more than 3 days
- The fever does not respond to fever-reducing medications, such as acetaminophen (Tylenol) or ibuprofen (Advil, Motrin)
Seek immediate medical attention if symptoms that accompany a fever include:
- Severe headache
- Unusual skin rash, especially if the rash worsens or spreads quickly
- Unusual sensitivity to light
- Neck pain and stiffness when looking downwards
- Confusion
- Persistent vomiting
- Shortness of breath or chest pain
- Severe abdominal pain, nausea, or vomiting
- Pain or burning with urination
- Seizures
What Causes Fever?
Causes of fever include:
- Viral or bacterial infection (most common cause)
- Heat exhaustion or heatstroke
- Certain inflammatory conditions such as rheumatoid arthritis
- Cancer
- Certain medicines, such as antibiotics, drugs used to treat high blood pressure, anticholinergics, and seizure medications
- Some vaccines, such as the diphtheria, tetanus and acellular pertussis (DTaP), pneumococcal vaccine, and measles vaccine
- Wearing clothes too warm for weather conditions
- Fevers caused by this are more common in newborns and infants because they don't regulate their body temperature as well as older children and adults
How Is Fever Diagnosed?
Fever can usually be diagnosed at home with a thermometer. There are several types of thermometers, including oral, rectal, ear (tympanic), and forehead (temporal artery).
Oral and rectal thermometers generally provide the most accurate core body temperature readings. Ear or forehead thermometers are less accurate. Doctors generally recommend taking temperature in infants with a rectal thermometer.
Depending on the symptoms that may accompany a fever, doctors may order additional tests to determine the cause of fever such as:
- Complete blood count (CBC) with differential
- Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP)
- Blood cultures
- Serum electrolytes, blood urea nitrogen (BUN), creatinine, albumin, and hepatic enzymes
- HIV test
- Tuberculin skin test (PPD)
- Urinalysis and urine culture
- Chest X-ray
What Is the Treatment for Fever?
Treatment for a mild fever is aimed at relief of symptoms and may include:
- Drink plenty of fluids to stay hydrated
- Rest
- Over-the-counter (OTC) fever reducers such as acetaminophen (Tylenol or ibuprofen (Advil, Motrin)
- Do not give aspirin to children because it may trigger Reye's syndrome, a rare but potentially life-threatening disorder
- Antibiotics
- If the fever is caused by a bacterial infection
- Antibiotics are not used to treat infections caused by viruses
Infants may need to be admitted to a hospital for treatment because fever may be a sign of a serious infection that requires intravenous (IV) medications.
What Are Complications of Fever?
A complication of fever in children between the ages of 6 months and 5 years is febrile seizures, which are seizures or convulsions triggered by fever.
How Do You Prevent Fever?
Because bacteria and viruses are frequent causes of illness that result in fever, it may be possible to prevent fever by preventing infection with these agents.
- Wash your hands frequently with soap and warm water for at least 20 seconds, especially after using the toilet, before eating, after being around a person who's sick
- Use hand sanitizer if you don't have access to soap and water
- Avoid touching the face, especially the mouth, nose, and eyes
- Cover your mouth when you cough and your nose when you sneeze
- Don’t share cups or utensils with someone who is ill
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