Body temperature is influenced by many factors, including the time of day, physical activity and fluid consumption, environmental temperature and humidity, stress, and the female menstrual cycle.
Despite these varying influences, normal body temperature falls within a relatively tight range, measured in degrees Fahrenheit (°F):
A fever happens when something raises your body temperature past its normal range. As one of the most common reasons for urgent care visits among patients of all ages, fever is usually a tell-tale sign of infection or illness.
A fever, or abnormally high temperature, is typically a sign of infection or illness. Because body temperature varies by person, time of day, and measurement technique; there’s no strict definition of what constitutes a fever.
Most health care providers recognize fever when a person’s body temperature reaches 100.4°F, measured orally. Compared to oral thermometers, ear thermometers typically measure one degree higher, and skin thermometers measure one degree lower.
A low-grade fever is a body temperature that’s slightly higher than normal but lower than 100.4°F. Most healthcare providers consider a body temperature between 99.5°F and 100.3°F to be a low-grade fever — a sign that the immune system is mildly activated.
A high-grade fever registers between 102.4°F and 105.8°F. Infection-related fevers seldom reach 105°F; the highest fever most people see is 104°F.
While it’s natural to feel some concern when you or your child comes down with a fever, common misconceptions about fever can cause needless worry and fear.
Fact: Fever is one of your body’s most important defenses against bacterial and viral infections. Essentially, a fever is your immune system’s way of making the environment less hospitable, impairing or slowing as many of these pathogens as possible.
No one wants to get sick, but most fevers are highly beneficial to ill children and adults, helping the body fight infection. The only exception? Infants younger than three months old should be seen by a doctor anytime they have a fever.
Fact: Simply put, fever fights for your body, not against it, helping you get better faster. Kids and adults alike should avoid taking fever-reducing medication unless the fever is causing discomfort or interfering with rest — which is most likely to happen when a fever reaches 102°F or higher.
Fact: Your brain has an internal thermostat that keeps your immune system response in check so that no fever can rise uncontrollably. This thermostat helps your body maintain the best temperature to fight infection.
This is why most infection-related fevers top out at 103°F or 104°F. But even when a fever reaches 105°F, it’s usually harmless — the brain knows when the body is too hot.
Fact: With treatment, fevers usually come down one or two degrees, at most, and only stay down until the medicine’s effects wear off. Simply put, medication only provides temporary relief from a fever; it doesn’t switch off this vital immune system response.
With most viral infections, fever lasts two or three days, always returning after treatment until the body finally overpowers the virus — which is usually by the fourth day.
Fact: A thermometer reading isn’t a complete indicator of how sick a person is; even a mild illness can cause a high-grade fever. Instead, it’s best to assess the seriousness of an infection or illness based on the severity of other symptoms.
For example, if your child eats, sleeps, and plays normally despite having a fever of 102°F, their illness is probably relatively mild. But if their fever is accompanied by a sore throat, coughing, body aches, vomiting, ear pain, or other bothersome symptoms — or if it persists longer than three days — it’s time to come see our urgent care team.
Fact: A high-grade fever caused by an infection generally isn’t harmful and can’t cause brain damage.
Body temperatures at or above 108°F can cause brain damage. Still, these dangerous, ultra-high body temperatures only occur with extreme environmental temperatures, such as what can happen inside a closed vehicle on a hot day.
If you or your child has a fever that concerns you, American River Urgent Care can help. Stop by our walk-in clinic in Orangevale, California, today. You can also call our office or click online to schedule a visit at your convenience anytime.
