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Definition Normal body temperature varies amongst people, but the average is 98.6 degrees Fahrenheit (37 degrees Centigrade). If the temperature is 99 to 100 degrees Fahrenheit, this may represent a low-grade fever. Body temperature of 100 degrees Fahrenheit or above is classified as fever.
Alternative Names Elevated temperature; Hyperthermia; Pyrexia
Considerations Normal body temperature varies during the day. It is generally lowest upon awakening in the morning. Food, extra clothing, excitement , and anxiety can all raise the body temperature. Strenuous exercise can also temporarily raise body temperature to as high as 103 degrees Fahrenheit. Extreme exercise, such as running a marathon, can raise body temperature as high as 107 degrees Fahrenheit, which can be dangerous (if sustained). A woman's menstrual cycle can also elevate temperature by one degree or more. Certain medications also cause an increase in body temperature. Most children have higher body temperatures than adults and seem to have more daily variation. Many infants and children develop high fevers, even with minor viral illnesses. A high fever does not directly cause brain damage. However, febrile seizures can occur in some children. Fevers are described as low grade (102 degrees Fahrenheit or lower) or high grade (above 103 degrees Fahrenheit). They are also described as either spiking (the fever suddenly jumps high, then drops) or cyclic (the fever increases and decreases in a regular manner). Bacteria, viruses, or their toxins may be released into the bloodstream and can cause chills and shivering in the patient with a fever. Chills can also occur during a temperature spike within a fever. Heatstroke can result from too much exercise without water or enough salt, and temperature can rise to 106 degrees Fahrenheit, which can be dangerous (if sustained). Unexplained fevers that continue for days or weeks are referred to by doctors as fevers of undetermined origin (FUO). Most are eventually found to be caused by a hidden infection.
Common Causes
  • Viral and bacterial infections
  • Colds
  • or
  • flu-like illnesses
  • Sore throats
  • and
  • strep throat
  • Earaches
  • (
  • otitis media )
  • Viral gastroenteritis
  • or
  • bacterial gastroenteritis
  • Acute bronchitis
  • Infectious mononucleosis
  • Urinary tract infections
  • Upper respiratory infections
  • (such as
  • tonsillitis , pharyngitis or laryngitis )
  • Medications (such as antibiotics, antihistamines, barbiturates, and drugs for
  • high blood pressure )
  • Occasionally, more serious problems like
  • pneumonia , appendicitis , tuberculosis (TB) , and meningitis
  • Fever can occur in infants who are overdressed in hot weather or a hot environment
  • Collagen vascular disease
  • , rheumatoid diseases, and
  • autoimmune disorders
  • Juvenile rheumatoid arthritis
  • Lupus erythematosus
  • Periarteritis nodosa
  • AIDS
  • and
  • acute HIV infection
  • Inflammatory bowel disease
  • Regional enteritis
  • Ulcerative colitis
  • Cancer
  • Leukemia
  • Neuroblastoma
  • Hodgkin's disease
  • Non-Hodgkin's lymphoma
  • Home Care
  • Fever is the body's natural response to a variety of conditions, such as infection. If the fever is mild and no other problems are present, no medical treatment is required. Drink fluids and rest. Evaporation cools the skin, and thereby reduces body temperature. Sponging or bathing in a tub of tepid water (about 98 degrees Fahrenheit) may help reduce the fever. Do not use cold water -- it is uncomfortable and is no more effective than tepid water. Do not use rubbing alcohol either, as it gets absorbed easily through the skin. If the victim is suffering from environmental heat-induced illness (heat exhaustion, heat stroke), remove the victim from the heat source. In addition to sponging with tepid water, place ice packs in the armpits, behind the neck, and in the groin. Begin administering fluids if victim is alert. Seek medical attention. Don't bundle up in blankets if the person shivers or becomes chilled. This will only cause a fever to rise. Medications (* see below) can be effective in fighting fever and chills. Medication should not be given by mouth to a child who is having seizures or who is unconscious. If heat illness is causing the fever, these medicines will not lower the body temperature and may even be harmful. For children:
  • If the child's temperature is over 102 degrees Fahrenheit, or if the child is uncomfortable, give acetaminophen or ibuprofen in either liquid or tablet form. Follow the recommended dose on the package label. DO NOT GIVE ASPIRIN TO CHILDREN UNDER THE AGE OF 17!
  • If the child's temperature is over 103.5 degrees Fahrenheit one to two hours after giving medication for fever, place the child in a tub of lukewarm water up to the navel. Rub a wet washcloth or towel over the child's body for 20 minutes or for as long as can be tolerated. Add warm water as needed to maintain the water temperature and keep the child from shivering. Pat (don't rub) dry with a towel.
  • If the fever persists and the child is older than six months old, or if it returns before the next dose of medication is due, consider alternating the acetaminophen and ibuprofen every 3 to 4 hours. This can be done safely, if the following precautions are met. Keep a written log of which medication was given and at what time. Make sure that you are waiting exactly 3 to 4 hours before each dose. Make sure that you are giving the correct dose of each medication. For example: 10 am- 1 tsp acetaminophen, 2pm- 1 tsp ibuprofen, 6 pm -1 tsp acetaminophen. Remember, even though these medications are sold over-the-counter, they can be fatal if you give too much, so be extra cautious of the timing and amount given if you choose to alternate medications. Be especially cautious with acetaminophen, which can harm the liver when given in excess. Ibuprofen is not recommended in infants less than 6 months old because their kidneys are not mature enough.
  • Dress the child in light clothing, give liquids, and keep the room cool but not uncomfortable.
  • Precautions in children:
  • Do not use ice water or rubbing alcohol to reduce a child's temperature.
  • Do not bundle a feverish child in blankets.
  • Do not wake a sleeping child to give medication or take a temperature -- sleep is more important.
  • (*) Medication precautions:
  • Aspirin use in children has been linked with
  • Reye's syndrome . This disorder may be fatal. Never give aspirin to a child under 17 years old.
  • Acetaminophen (Tylenol) is as effective as aspirin in fever reduction. However, acetaminophen can, in rare cases, cause liver damage when used in high dosages. It is safe if taken at usual dosages.
  • Ibuprofen should not be given to infants under 6 months of age.
  • During an
  • acute illness, fever may rebound a few hours after initial acetaminophen administration. It is recommended to give the medication at regular intervals during the course of an illness.
    Call your health care provider if
  • There is stiffness of the neck,
  • confusion , significant irritability, or sluggishness.
  • An infant younger than 6 months has any fever.
  • A child between 6 months and 1 year old has a fever that has lasted more than 24 hours.
  • The fever remains above 103 degrees Fahrenheit after an hour or two of home treatment.
  • The fever has not gone away in two days.
  • If you think you may have incorrectly dosed the acetaminophen or ibuprofen.
  • Anyone with a temperature above 105 degrees Fahrenheit should be examined for heat illness, stroke, or drug overdose.
    What to expect at your health care provider's office The medical history will be obtained and a physical examination performed. Medical history questions documenting your fever in detail may include:
  • Quality
  • Is it low grade (102 degrees Fahrenheit or lower)?
  • Is it high grade (103 degrees Fahrenheit or higher)?
  • Time pattern
  • The fever lasted for how many days or weeks?
  • Is it increasing? Is it increasing rapidly?
  • Has the fever gone away (resolved)?
  • How long did it take for the fever to go away (how many days)?
  • Do you have alternating chills and fever (relapsing)?
  • How frequently does it alternate (at what sort of an interval – days, hours)?
  • Did it occur within four to six hours after exposure to something that you might be allergic to?
  • Does the fever occur in an undulating up and down pattern (is it high, then lower, then high)?
  • Did it develop suddenly?
  • Does the temperature go up and down suddenly (spike) or does it change slowly (cyclic)?
  • Does it go away and then come back again daily (recurrent)?
  • The physical examination may include detailed examination of the skin, eyes, ears, nose, throat, neck, chest and abdomen to look for the cause of the fever. Treatment depends on the duration and cause of the fever, and on other accompanying symptoms. Diagnostic tests that may be performed are:
  • Blood studies, such as a
  • CBC or blood differential .
  • Urinalysis
  • .
  • Sputum culture
  • .
  • Spinal tap
  • .
  • X-ray of the chest
  • .
  • After seeing your health-care provider, you may want to add a diagnosis related to fever to your personal medical record.

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