Healthy Living

What Causes a Fever?

What Causes a Fever?

Fever is a temporary increase in the body’s temperature usually caused by an illness. It can affect both children and adults, and it is one of the leading medical symptoms. The body’s average normal temperature is 98.6 degrees Fahrenheit. During a febrile condition, the core body temperature can vary between the temperatures of 99.5 ° F and 100.9 °F, although the value of the upper limit is debatable, as the temperature can reach up to 107.6 ° F. Fever is medically known as controlled hyperthermia or pyrexia.

A fever renders the victim feeling cold due to an elevated rate of muscle contraction. After reverting back to the normal condition, the normal body temperature recovers, and the patient feels hot and starts sweating, which is a sign of a decreasing fever. In some rare cases, the patient may be affected by a fever fit or seizure, which may be congenital. This is mostly seen in children and infants.

Having a fever can be an indication that something is wrong in the body. A fever can be uncomfortable for an adult, but it isn’t usually an area of concern unless the increase in temperature is 39 degrees Celsius or higher, while a fever in infants and toddlers is a sign of a serious infection. If the fever is not severe, then treatment should not be preferred, as it keeps the body’s immune system strong and lasting. Being a defense mechanism against infections both bacterial and viral, a fever increases the adeptness of the bodily immunity.

Though a high temperature is central to a fever, it should not be confused with similar symptoms caused by night sweats, hyperthermia, or even hot flashes. Only with proper temperature evaluation by a thermometer can a fever be confirmed.

Depending on the cause of the fever, some of the observable signs and symptoms are:

  • Sweating excessively
  • Headache
  • Shivering
  • Palpitation and a rapid heart rate
  • Muscle aches
  • Flushing of the skin
  • General weakness
  • Pain or soreness of the eyes
  • Dehydration
  • Feeling lightheaded or dizzy
  • Loss of appetite

When the temperature goes up, it will come to a point where the temperature will stop rising, which is known as a plateau event.

The development of fever is the body’s way of fighting a number of infections. However, in some cases, it can rise so high that the fever can become serious and can result in complications, such as hallucinations or confusion.

Fevers go away within a few days most of the time. Over-the-counter medicines, such as antipyretics, are also available. They can help lower the body’s temperature. According to healthcare professionals, there is no need to try to bring the temperature down if the fever is only mild, since it might be neutralizing the virus or bacterium that’s causing the infection.


Causes of Fever

Fever happens when the hypothalamus, an area in the brain, shifts the set point of the body’s normal temperature upward. Because of this, a person will feel chilled, thus adding layers of clothes or wrapping in a blanket. The body may also shiver to create more body heat, which will result in an increased body temperature after quite some time. All of the aforementioned responses are the result of pyrogens (fever causing substances) like bacteria, viruses, fungi, or toxins that set off a response by the body’s immune system, and hence the hypothalamus is stimulated to raise the normal temperature of the body to ward off the infection. Though it is not a communicative disease, when caused by a contagious invader, it may spread through different mediums.

The body’s temperature varies throughout the day. It can be higher in the afternoon or evening and lower in the morning. Although 37 degrees Celsius is considered to be the normal level, people’s temperature can vary from 36.1 degrees Celsius to 37.2 degrees Celsius. Heavy exercise and menstrual cycles can also affect the body’s temperature.

Fever can be caused by:


In some cases, the cause of fever is not identified. For a fever that has been persistent for more than three weeks without a known cause, the fever is stated to be caused by an unknown origin.

A fever is a sign of a medical emergency when accompanied by the following symptoms.

  • Swelling of the throat
  • Stiffness and pain in the neck
  • Unbearable headaches
  • Persistent pain while urinating
  • Worsening skin rash
  • Excessive irritation and vomiting tendency
Low Grade Fever

Treatment for Fever

The primary diagnosis involves a physical examination followed by some routine blood tests. If the cause is still not known and the fever prevails, then the doctor might want to admit the patient in a hospital for thorough observation. In rare situations, there are cases where the fever is unresponsive to treatment.

Treatment for fever depends on how severe it is. For a low grade fever without any other symptoms, it can be treated at home with bed rest and drinking fluids. No medical care is necessary. However, if fever is accompanied by other symptoms, such as dehydration and discomfort, medical treatment is needed.


There are a lot of ways to prevent a fever, and most of them include a method to restrict the infectious agents from manifesting in the body. Some of the helpful methods are:

  • Practicing proper sanitation and hygiene by washing both hands before and after meals and after using the toilet (especially in the company of other people) and keeping the home environment clean and pest free.
  • Avoiding sharing of cups, utensils, and even glasses with other people.
  • Being wary of sneezing in the open and inhaling other people’s coughs.

Seeking advice from a medical professional is crucial, because it will help stop a fever in its tracks so that it doesn’t cause further problems and turn into a bigger issue.

Key Takeaways

  • The body’s average normal temperature is 37 degrees Celsius.
  • Fever is medically known as pyrexia or hyperthermia.
  • In some cases, the cause of fever is not identified.