What Causes a Fever?

A fever can cause worry and grief in parents, especially as they battle with the condition late at night.

A fever is the result of the body fighting off a foreign invader such as viruses, bacteria, fungi, drugs, or other toxins. Fever is a common symptom of most infections. In children, immunizations or teething in may cause low-grade fever. Autoimmune disorders, medication reactions, seizures, or cancer may also cause fevers.

A temperature greater than 100.4 degrees in adults or children is considered a fever. A thermometer is used to determine the temperature. Digital thermometers can be used to measure rectal, oral, or axillary (under the armpit) temperatures. Axillary are not as accurate as rectal or oral measurements, and generally measure 1 degree lower than a simultaneously obtained oral temperature.

Signs and symptoms of a fever include the following: temperature greater than 100.4 degrees in adults and children; shivering, shaking, chills; aching muscles and joints; headache; intermittent sweats; rapid heart rate or palpitations; skin flushing; feeling faint, dizzy, or lightheaded; and weakness.

Seek medical attention if the temperature is higher than 104 degrees or causes convulsions, hallucination, or confusion. Any child below 3 months of age who has a temperature of 100.4 degrees or greater should be seen by a physician.

Generally, if the fever does not cause discomfort, the fever itself need not be treated. Encourage rest and plenty of fluids. Some research studies suggest that children actually fair better by not treating a fever, as long as there are not any other underlying viruses present. Keep the individual comfortable and not overdressed, which can cause the temperature to rise further. Tepid water baths are a home remedy that may help bring down a fever.

Fever-reducing medications such as acetaminophen and ibuprofen may be used at home. 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, or flu) has been associated with Reye’s syndrome. Reye's syndrome is a dangerous illness which causes prolonged vomiting, confusion, and even coma and liver failure.

If the fever accompanies a simple cold or virus, you can treat the fever as noted and be assured that the fever is only a symptom of the illness. However, if there are other symptoms or if the fever becomes bothersome, contact your doctor.

By Joe Lamb, MD, ThedaCare Physicians-New London.