Fever.

A fever is a body temperature that is higher than normal. It is not an illness. It is part of your body's defense against infection. Most bacteria and viruses that cause infections do well at the body's normal temperature (98.6 F). A slight fever can make it harder for them to survive. Fever also activates your body's immune system.

How should I take a temperature for fever?

Measuring an axillary (under the armpit) temperature for fever:

Axillary temperatures are not as accurate as rectal or oral measurements. Studies show that glass thermometers must be left in place for approximately 10 minutes to accurately measure an axillary temperature. An axillary temperature will read approximately 1 degree lower than a simultaneously obtained oral temperature.

Measuring fever by oral temperature:

Older children and adults can have their temperature taken under the tongue with their mouth closed. A standard glass and mercury thermometer should be left in place for at least three minutes. Make sure to shake down the thermometer before using it. The tip of the thermometer should be placed as far back under the tongue as possible. Oral temperatures will be inaccurate if you have had hot or cold drinks within 20 minutes of temperature measurement.

Measuring fever by rectal temperature:

Infants should have rectal temperature measurements. A standard glass and mercury thermometer should be left in place for a minimum of 3 minutes. Make sure to shake down the thermometer before using it. Appropriate care should be taken in inserting, maintaining and withdrawing the rectal thermometer. To take a rectal temperature safely, place the child prone (stomach-side down) on a firm surface. After separating the buttocks, insert a lubricated thermometer approximately 1 inch into the rectum. After at least three minutes, remove the thermometer. A rectal temperature will read approximately 1 degree higher than a simultaneously obtained oral temperature.

Depending on what's causing your fever, additional fever symptoms may include:
* Sweating
* Shivering
* Headache
* Muscle aches
* Lack of appetite
* Dehydration
* General weakness

Very high fevers, between 103 and 106 F, may cause:
* Hallucinations
* Confusion
* Irritability
* Convulsions

Fever-induced seizures.

About 4 percent of children younger than age 5 experience fever-induced seizures (febrile seizures). The signs of febrile seizures, which occur when a child's temperature rises or falls rapidly, include a brief loss of consciousness and convulsions.

How is fever treated?

Generally, if the fever is not causing a person to be uncomfortable, the fever itself need not be treated. It is not necessary to awaken an adult or child to treat a fever unless instructed to do so by your health-care practitioner. If you wish to treat a fever, acetaminophen (Tylenol and others) can be used to lower a fever. The recommended pediatric dose can be suggested by the child's health-care worker. Adults without liver disease or other health problems can take 1000 mg (two "extra strength" tablets) every four to six hours. Ibuprofen (Motrin/Advil) can also be used for fever in patients over 6 months of age. Again, discuss the best dose with your doctor. For adults, 400-600 mg (two to three 200 mg tablets) can be used every six hours. Aspirin should not be used for fever in children or adolescents. Aspirin use in children and adolescents during a viral illness (especially chickenpox and influenza) has been associated with Reye syndrome. Reye syndrome is a dangerous illness which causes prolonged vomiting, confusion, and even coma and liver failure.

An individual with a fever should be kept comfortable and not overdressed. Overdressing can cause the temperature to go higher. Tepid water [85 degrees F (30.0 degrees C)] baths may help bring down a fever. Never immerse someone in ice water. This is a common misconception. Never sponge a child or an adult with alcohol; the alcohol fumes may be inhaled causing many problems.

References :
1.http://www.medicinenet.com/aches_pain_fever/page2.htm#2howis.
2.http://www.nlm.nih.gov/medlineplus/fever.html
3.http://www.mayoclinic.com/health/fever/DS00077/DSECTION=2