What Causes a Fever?

Understanding Fevers

A fever is the body’s way of defending itself from bacteria and viruses. It is a common symptom in which the body’s internal temperature rises to levels above normal. When a fever is suspected, the body’s temperature is taken with a thermometer. If the levels are at the following, then a fever is present:

• Temperature in the mouth (oral) is at or over 37.5 °C (99.5 °F)
• Temperature under the arm (axillary) is at or over 37.2 °C (99.0 °F)
• Temperature in the anus (rectum/rectal) or in the ear (otic) is at or over 38.0°C (100.4°F)

Levels of Fevers

Fevers are classified into categories based on their severity and help determine when to seek medical advice:

• Low Grade fevers usually range from 38 – 39°C (100.4 – 102.2°F). Typically, no medical intervention is necessary with low-grade fevers. Fever reducers such as, acetominophen or ibuprofen, are often effective in lowering these temperatures.
• Moderate fevers usually range from 39 – 40°C (102.2 – 104.0°F). For moderate fevers, contact your pediatrician to determine if medical assistance is necessary.
• High Grade fevers usually range from 40 – 42°C (104.0- 107.6°F). Fevers at this level require medical intervention. Contact your pediatrician or local hospital right away for further treatment instructions.
• Hyperpyrexia occurs when a fever reaches levels above 42°C (107.6°F). Fevers this high are classified as medical emergencies and require immediate medical assistance.

Treating Fevers

There are many causes of a fever, and one of the most common is influenza, or the flu. While we are quick to stop a rising fever, it is a good sign that the body is fighting off the sickness. One of the most important things to do when a fever occurs is stay hydrated. Water is the most favored beverage, but sports drinks and electrolyte-replacing drinks designed specifically for preventing dehydration are also effective.

The main concern is keeping the fever under control so that it does not rise to dangerous levels. This is often accomplished by administering acetominophen (Tylenol) or ibuprofen (Motrin). Be sure to carefully monitor the dosage and use age appropriate (Children or Infant) formulas. DO NOT give children any medication that contains aspirin as this can cause a disease of the liver known as Reye’s Syndrome.

Heat from a fever can also be removed by applying cold cloths to the forehead or bathing in tepid water. For children too small for medication, applying cool cloths or a tepid bath can offer relief safely.