So it hits you right in the middle of the day. You start feeling sluggish. You get chills and a headache. Maybe you feel a little bit irritable. You reach for the thermometer, stick it under your tongue, and sure enough it reads 100.0° Fahrenheit. You have a low-grade fever. But what causes a fever?

What is Fever?

Fever is a natural response that helps fight off foreign substances such as viruses, bacteria, fungi, and toxins. Body temperature is set by the thermoregulatory center, located in an area of the brain called the hypothalamus. The hypothalamus knows what your body temperature should be (usually 98.6° Fahrenheit) and will send messages to your body to keep it that way.

Unfortunately, many illness-causing microbes do best at the body’s normal temperature. A fever raises the temperature beyond which certain microbes need to reproduce. When this happens, you may feel chilled and add layers of clothing or wrap up in a blanket, or you may shiver to generate more body heat, eventually resulting in an elevated body temperature.

Body Temperature

Body temperature is not constant all day, but is lowest at 6 A.M. and highest around 4-6 P.M. In addition, temperature varies in different regions of the body. A low-grade fever is often classified as an oral temperature that is above 98.6° F but lower than 100.4° F  for a period of 24 hours.

A fever of 103° or higher is more concerning in adults.

In children a normal body temperature for a healthy child is between 97 and 100.4 degrees Fahrenheit. If your child’s temperature is above this range, he has a fever. A baby can have a low-grade fever and be seriously ill or a high fever and be only mildly ill. But if a baby under 3 months of age has a fever of 100.4 degrees F or higher, he should be examined by a medical professional.

Fever is Not Illness

It’s important to remember that by itself fever is not an illness. It’s usually a symptom of an underlying problem. Fever has several potential causes including:

• A virus
• A bacterial infection
• Heat exhaustion
• Certain inflammatory conditions such as rheumatoid arthritis — inflammation of the lining of your joints (synovium)
• A malignant tumor
• Some medications, such as antibiotics and drugs used to treat high blood pressure or seizures
• Some immunizations, such as the diphtheria, tetanus and acellular pertussis (DTaP) or pneumococcal vaccine

You can treat a fever with over the counter medications such as acetaminophen or ibuprofen, but a small but growing body of research shows that letting a fever run its course may reduce the length and severity of such illnesses as colds and flu.

Prevent Fever

You may be able to prevent fevers by reducing exposure to infectious diseases. Here are some tips provided by the Mayo Clinic that can help:

• Wash your hands often and teach your children to do the same, especially before eating, after using the toilet, after spending time in a crowd or around someone who’s sick, after petting animals, and during travel on public transportation.
• Show your children how to wash their hands thoroughly, covering both the front and back of each hand with soap and rinsing completely under running water.
• Carry hand sanitizer with you for times when you don’t have access to soap and water.
• Try to avoid touching your nose, mouth or eyes, as these are the main ways that viruses and bacteria can enter your body and cause infection.
• Cover your mouth when you cough and your nose when you sneeze, and teach your children to do likewise. Whenever possible, turn away from others when coughing or sneezing to avoid passing germs along to them.
• Avoid sharing cups, water bottles and utensils with your child or children.

If you or your child has a cold, we offer walk-in services for acute illnesses such as fever and respiratory illness. You can also schedule an appointment by calling  (662) 348-3342. We’ll be happy to help you.