Before we get into what causes a fever, it is helpful to understand what a fever is and why we get a fever. The average temperature of the human body is around 98.6°F (37°), but can vary by 1°F (0.6°C) depending where the temperature is taken, the person, the time of day and your activity level.
What is a Fever?
A temperature slightly above normal to a temperature of 100.4°F (38°C) is called a low grade fever and usually not a cause for worry unless it continues to rise. A temperature that is higher than a low grade fever should be monitored and a fever of 104°F (40°C) or higher can be dangerous and a doctor should be called immediately. A high fever can cause convulsions and delusions, especially in infants, children and the elderly.
A fever is actually one of our body’s healing defense mechanisms. When we get sick and get a fever, our body is actually trying to kill what made us sick in the first place. The most common causes of a fever are illnesses due to a virus or bacteria. Since viruses and bacteria cannot live at higher temperatures, the body’s immune system uses fever to stop the illness. In other words, that fever that makes us feel so miserable is actually trying to heal us by killing what is making us sick. For this reason, it is usually best to let a low grade fever run its course, unless there are other severe medical symptoms.
What Can Cause Fever
Fevers are the body’s way of protecting itself from an outside invader, and a function of our immune system, which runs to the rescue any time we get sick. The invader can be a virus, bacteria, drugs, toxins or fungi.
Common causes of a fever include:
- Colds and flu
- Strep throat
- Food poisoning
- Dental problems
- Blood poisoning
- Illegal drugs
Immunizations like the flu shot, pneumococcal vaccine and the diphtheria, tetanus and acellular pertussis (DTaP) shot can cause a low grade fever for a short while after the shot was taken.
Heatstroke is caused from overexertion in hot and humid weather and usually causes a high fever and can be a life threatening medical condition. If you are around someone you suspect of having heatstroke, you should get them to a doctor or hospital right away.
Symptoms of a Fever
We know when we start to get that flu feeling, and then we confirm that we do have a fever using a thermometer. Other than using a thermometer to check our temperature, other symptoms of a fever include:
- Intermittent or excessive sweating, (sometimes called breaking a fever)
- Shaking, chills and shivering
- Body aches
- Hot skin
- Pain around the eyes
- Hallucinations with high fevers
There are other conditions for women that are not a fever such as night sweats and hot flashes during menopause.