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Common Cold

Information, Symptoms, Treatments and Resources


What is a Fever and How to Treat a Fever?


Causes, symptoms and treatments for a fever 

By Katherine Solem


A fever is when your body's temperature increases above its regular state. For an adult, a fever usually constitutes a temperature above 99 - 99.5 °F (37.2 - 37.5 °C) and occurs most often when the body is fighting off an infection. Most commonly, this can be treated with over the counter medications including acetaminophen (Tylenol) and ibuprofen (Advil, Motrin). Here are some more details about the causes, symptoms and treatments for a fever.

Causes of a Fever  

  • Virus: When you have a virus, your body's immune system works to fight it off. Part of this immune response causes your body's temperature to increase causing you to have a fever.
  • Bacterial infection: Your body temperature can also increase and cause a fever when you are fighting off bacterial infections.
  • Heat exhaustion: Because a fever is marked by an increase in your body's temperature, physical overheating can cause a fever.
  • Extreme sunburn
  • Autoimmune or inflammatory disorders: Because a fever is part of your immune response, autoimmune or inflammatory disorders often involve fevers. This can include disorders such as rheumatoid arthritis, Crohn's disease, ulcerative colitis and vasculitis.
  • Cancer: While it is not always the case, a fever can sometimes be the first sign of cancer.
  • Immunizations: An immunization works by introducing small quantities of the foreign agent you are immunizing against into your body. As a result, it is not uncommon for a fever to occur, particularly in children, following an immunization.


Symptoms of a Fever

  • In Children: 
    • Measured in bottom (rectally): Temperature above 100.4 °F (38 °C)
    • Measured in mouth (orally): Temperature above 99.5 °F (37.5 °C)
    • Measured in arm (axillary): Temperature above 99 °F (37.2 °C)
  • In Adults: A temperature above 99 - 99.5 °F (37.2 - 37.5 °C) constitutes a fever.


Symptoms That May Accompany a Fever


Treatments for a Fever

The general treatment for fevers is medication. Do not give any medication to children under 3 months old until you have spoken to a doctor. The dosage of each medication is based on your weight. Detailed instructions can be found on the label of each medication.


  • Acetaminophen (Tylenol):
    • Who can take: Adults and children
    • Instructions: Take every 4-6 hours
  • Ibuoprofen (Advil, Motrin): 
    • Who can take: Adults and children over 6 months old
    • Instructions: Take every 6-8 hours.
  • Aspirin:
    • Who can take: Adults only. DO NOT give it to a child as it can cause Reye's syndrome - a rare but serious disease that affects children only. 


Home Remedies for a Fever

These home remedies can help you feel more comfortable when you have a fever, but most of them work best in conjunction with medication.

  can help rehydrate them.

  • Drink lots of fluids: You've probably heard this before, but drinking lots of water, juice or both can help replenish your body's fluid and help you get better. If your child is less than a year old, drinks like Pedialyte can help rehydrate them.
  • Rest: Not only does resting help your body use its energy to fight off any infections but being active can actually increase your body temperature further.
  • Stay cool: Even if you have the chills, try to wear light clothing and sleep with a thinner blanket.
  • Soak in lukewarm water: Taking a 5 - 10 minute lukewarm bath can help cool off your body and lower your temperature.


How to Prevent a Fever

  • Wash your hands with soap: Because most fevers are caused by viruses, an easy way to avoid fevers is to stay healthy! Make sure to wash your hands with soap throughout the day, particularly before meals, to reduce the likelihood of infection.


Katherine Solem is a health writer and editor living in San Francisco. 

Published: July 1, 2011

See also:

Keep track of your temperature with our temperature tracker
Find out the difference between the common cold and the flu
But do they work? We put 7 popular cold and flu remedies to the test


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