A Fever, also known as hyperthermia or pyrexia, is when your body temperature is higher than is considered normal. A normal temperature lies within the 97 to 99 degree Fahrenheit range.
The part of your brain that regulates temperature, the hypothalamus, causes fever in reaction to illnesses, infections, and certain medications. A fever occurs when small molecules in the blood (called pyrogens) cause the hypothalamus to “reset” your body temperature.
The symptoms of a fever include chills or shivering, a headache, loss of appetite, dehydration, sweating, and feeling weak. A fever is part of the immune system’s response to fight off bacteria, viruses, and infections.
A fever indicates that something is going on inside your body, and it’s a symptom, not an illness. Here are eight common causes, and what to do to bring down a fever.
1. Bacterial Infections
Fevers can be caused by infections of the throat, ear, lung, bladder, or kidneys. While most bacteria is harmless, just under 1% cause diseases that have a fever as a side effect.
2. Viruses
A fever is most commonly caused by viruses that cause colds and flu, including COVID-19, adenovirus, enterovirus, influenza, and parechovirus.
Someone who is infected with a virus spreads it by sneezing, breathing, or touching people or surfaces. To avoid becoming infected, wash your hands frequently and disinfect surfaces often.
3. Inflammatory Conditions
Autoimmune diseases cause fevers because a person with an autoimmune diseases’ immune system attacks healthy cells, which triggers an inflammatory response and the production of pyrogens.
There are more than 80 different autoimmune diseases, including rheumatoid arthritis and lupus, that affect many different parts of the body.
4. Medications
Certain medications that are known to cause drug-induced fevers include penicillin and other stimulants like Ritalin and Dexedrine. Thyroid hormone medications like Synthroid can also raise body temperature and cause a fever.
5. Heat Exhaustion
The symptoms of heat exhaustion are sunburn and heatstroke, which cause increased sweating and dehydration. Dehydration and heat stress can lead to a dangerously high core temperature, which leads to a high fever.
Heat exhaustion and heat stroke can also be caused by strenuous exercise in a hot environment. Usually, your body will cool itself off by dilating blood vessels and producing sweat. It’s rare, but sometimes these systems can malfunction, and you’ll get a fever.
6. Hormone Disorders
Endocrine disorders like hyperthyroidism, hypothyroidism, and other hormonal imbalances cause sudden episodes of sweating and fever.
7. Malignant Tumors
Tumors produce pyrogens that affect the hypothalamus, which indirectly causes fevers, and cancer treatments can also directly cause fevers.
8. Immunizations
Certain vaccinations such as diphtheria, tetanus, and MMR (measles, mumps, and rubella) shots can cause fevers because they trigger an immune response.
How to Treat a Fever
For a mild to moderate fever (under 102 degrees Fahrenheit) in adults, doctors recommend drinking plenty of fluids to prevent dehydration, cool your body down, and replace electrolytes.
It’s also helpful to eat light foods that are easy to digest and get plenty of rest so that your body can recover. Taking lukewarm baths and keeping yourself cool can also help alleviate the discomfort associated with a fever.
Medications that contain ibuprofen, acetaminophen, or aspirin can be taken to reduce your fever. However, a fever is usually a sign that your immune system is working, so there is some controversy around whether you should suppress it or ride it out.
Because a fever is a symptom and not an illness, your doctor will treat the root cause of the fever. For bacterial infections, you may be prescribed antibiotics. If the cause is a viral infection, your doctor may prescribe NSAIDs (non-steroidal anti-inflammatories).
Sometimes, doctors will prescribe antipyretics to lower a person’s temperature.
When to Seek Medical Help
Although fevers are not usually serious in themselves, you should seek immediate medical attention if you experience convulsions, loss of consciousness, confusion, a stiff neck, have trouble breathing, pain upon urination, or severe pain anywhere in your body (especially the chest or abdomen).
A high temperature in infants is more dangerous than a high temperature in adults – consult a medical professional if an infant has a temperature of 102 degrees Fahrenheit or higher and has other accompanying symptoms of illness, such as a cough, a rash, or diarrhea.
Most fevers caused by common illnesses will resolve on their own. However, if your temperature is above 106 degrees Fahrenheit for extended periods, seek medical treatment.
