You Probably Don't Need to Treat a Fever
Sometimes, the human body runs hotter than normal. Whether due to infection or some other condition, the hypothalamus increases the body's temperature above the normal range, which is between 97.6 °F and 99.5 °F. Blood vessels near the skin constrict to retain heat and shivering may begin, leading the muscles to generate heat. The resulting state is called pyrexia, but it's more commonly known as a fever.
Here is about as far as the condition usually goes. A hand on the forehead reveals the situation, while a thermometer under the tongue confirms it. What comes next, recommended by Dr. Moms everywhere, is a dose of ibuprofen or acetaminophen. These drugs block fever-inducing signals from the hypothalamus, causing the body's temperature to return to normal.
But is this the correct course of action? While treating a fever seems like commons sense, science presents a more nuanced view.
"Fever retards the growth and reproduction of bacteria and viruses, enhances neutrophil production and T-lymphocyte proliferation, and aids in the body’s acute-phase reaction... Most fevers are of short duration, are benign, and may actually protect the host. Data show beneficial effects on certain components of the immune system in fever, and limited data have revealed that fever actually helps the body recover more quickly from viral infections..."
Despite the potential benefits of fever, many people suffer from what researchers have termed "fever phobia." Though there is no evidence that fever worsens an illness or causes long-term neurologic complications, many believe that it does. As Clay Jones reported at Science-Based Medicine:
"A 2001 paper revisiting fever phobia published in Pediatrics revealed that 91% of caregivers thought fever could cause harmful side effects including seizure (32%), brain damage (21%) and death (14%). Coma and blindness also made the list. With the exception of febrile seizures, a common and benign entity seen only in young children, fever just doesn’t do these things."
Much of the misunderstanding arises from confusing another condition, hyperthermia, with fever. They are not the same. Hyperthermia is potentially life-threatening, uncontrolled bodily overheating on account of an outside source. Fever is a controlled, internal process, which rarely, if ever, raises the body's temperature to a point where actual harm can be done.
A surprisingly small amount of scientific studies have actually examined the effects of treating versus not treating a fever in humans. According to a recent systematic review of randomized, controlled trials, there doesn't seem to be any difference in outcomes in treating or not treating a fever in critically ill patients. On the other hand, treating a fever may slightly increase the severity of the common cold and pneumonia.
So if fever is potentially beneficial and rarely harmful, does that mean one should never treat a fever? Not at all. Fever can be very uncomfortable and can lead to lost sleep and dehydration, and when you're sick, both sleep and hydration are vital to getting better.
You should also call your doctor for a fever over 102 °F in children and 104 °F in adults.
In the end, treating fever should not be about reducing a number, but rather about alleviating symptoms. If you or a child is feeling miserable at 102 °F, go ahead and take that fever-reducer. If you decide to let the fever run it's course, that's okay, too.