Doctors debate benefits and detriments of fevers

Dear Doctor: I’m confused about fever. What is considered a fever? And if fever is the result of a person’s body fighting a disease, why is it bad for us? It seems to make no sense to treat a person by lowering their fever.

Dear Reader: You’ve asked a fascinating question that, believe it or not, has been a subject of debate for thousands of years.

As you point out, a fever isn’t a disease. Rather, it’s most often a sign that the body is rallying to fend off an infection or illness. What people haven’t been able to agree on is whether or not the fever is beneficial because it fights the invader, or detrimental because of its damaging toll on our bodies.

One line of thinking goes that if an elevated core temperature is helpful at fighting off an illness, we shouldn’t interfere. That’s an idea that dates all the way back to Hippocrates. In fact, the practice of pyrotherapy -- medically inducing a fever -- was used as recently as the late 19th and early 20th century to manage certain types of bacterial infections. Pyrotherapy was largely abandoned once the discovery of penicillin ushered in the era of antibiotics.

The opposing argument is that the metabolic costs of having a fever outweigh the potential benefits. For example, even a moderate fever may pose a danger to people with heart or lung conditions, because it causes heart and respiratory rates to increase. Fever can also adversely affect the mental state of someone with dementia. That means in order to avoid potential complications, fever should be treated.

Small studies have yielded evidence that supports each side of the fever argument. The fact is that centuries later, we still don’t have a definitive answer.

What we do know is that fever is defined as a body temperature of 100.4 degrees Fahrenheit (that’s 38 degrees Celsius) and up. The most common causes of fever are upper and lower respiratory tract infections, gastrointestinal infections and urinary tract infections. Heatstroke, sunstroke, certain cancers, reactions to drugs, allergic reactions and autoimmune disorders can also cause fever.

Eve Glazier, M.D. and Elizabeth Ko, M.D

Symptoms that accompany a fever typically include headache, muscle aches, sweating, chills and shivering, loss of appetite, weakness and generally feeling crummy. Most adults can tolerate temporary fevers up to 104 degrees F. However, this type of fever may signal additional underlying problems. We recommend checking with your doctor if your fever reaches 103 degrees F or more.

To reduce a fever, adults and children over the age of 6 months can use over-the-counter medicines such as ibuprofen or acetaminophen. Although adults can treat a fever with aspirin, it should never be given to children; the use of aspirin in children has been linked to Reyes syndrome, which is a rare but serious condition that causes swelling in the liver and brain.

Taking a lukewarm -- not cool or cold -- shower, bath or sponge bath can also bring relief. You should rest when you have a fever, and drink plenty of fluids to stay hydrated. When any type of fever is persistent or becomes recurrent, it’s important to see your doctor.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)


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