What is a fever?
A fever is a physiological problem when your body temperature is above the normal range. An elevated body temperature usually accompanies an underlying condition. Your body increases your temperature to help fight infection or signal a problem from within.
A fever is determined when your body temperature rises above the normal range of 98 to 100 degrees Fahrenheit. As your temperature rises, you may feel like you have the chills. Your immune system is trying to remove the cause of your illness by making a fever. Normally, it will resolve on its own within a week at the most.
Signs and symptoms of fever
Sweats or chills
You might experience sweats or “chills”—feeling cold while shivering. These symptoms might be a sign that you have a fever.
Lack of appetite
If you have a fever, you might find your appetite to be lacking. A variety of infections can cause a fever accompanied by a lack of appetite.
Restlessness occurs when you’re struggling to rest or relax. There is a chance you will feel restless if you’re experiencing a fever.
Weakness or fatigue
A fever can cause you to feel fatigue or weakness—a decrease of strength in your muscles.
If your fever becomes too high or is prolonged you may also feel irritable, confused, delirious, or you might endure seizures. If you experience any of these additional symptoms you should seek medical attention immediately. This could be a sign of a severe illness or severe fever.
Types of fever
Because fevers have so many different causes, they can be difficult to type, and the categories aren’t always very helpful. Fevers are usually measured based on how long they last and how high your temperature gets. Doctors have classified five main types of fever including:
This fever has a fluctuating baseline between normal temperatures and fever levels over the course of the day.
This type of fever may come and go, and temperature fluctuates, but though it falls, it never falls all the way back to normal.
Either an intermittent or a remittent fever is considered hectic if the temperature range swings widely throughout the day, with a difference of at least 1.4 degrees Celsius between the highest and lowest temperatures.
Also called a “sustained” fever, this is a prolonged fever with little or no change in temperature over the course of a day.
This is a type of intermittent fever that spikes up again after days or weeks of normal temperatures. This type of fever is common with animal bites and diseases like malaria.
Causes of fever
Your body will create a fever for a variety of issues. Some of the most common issues include:
This is the most common cause for a fever. Your body will raise your temperature to fight off bacteria or viruses in your body. This includes colds, flu, gastroenteritis, or ear, skin, throat, or bladder infections.
These disorders include hyperthyroidism that can elevate your body temperature.
When to see the doctor for fever
If you have a fever over 104 degrees Fahrenheit, you need to schedule an appointment with your doctor immediately. Especially if you are also experiencing the following symptoms in addition to your high fever:
- Loss of consciousness
- Stiff neck
- Trouble breathing
- Severe body pain
- Swelling or inflammation of body parts
- Pain when urinating
- Persistent headache
Your doctor will determine the proper treatment plan for you and try to diagnose the underlying cause of your fever.
If you have a thermometer, you can determine if you have a fever at home. You will put the thermometer under your arm or under your tongue. If you go to your doctor for a high fever, they will diagnose you by taking your temperature. Your doctor will also work to diagnose the underlying cause of your fever.
Treatments for fever
A fever is your body’s defense against infection and illness. Typically, your fever will go away on its own. While the fever is working through your body, there are ways to help you feel better. They include:
Plenty of fluids
It is important to drink plenty of fluids to help cool your body and prevent dehydration. Especially if you have the flu or gastroenteritis which may cause you to lose many fluids. Drinking water, broth, or electrolyte drinks can help replenish those fluids.
Nonsteroidal anti-inflammatory drugs (NSAIDs) will help relieve your head and body aches and reduce your body temperature. These include ibuprofen (Advil or Motrin), naproxen (Aleve), aspirin, or acetaminophen (Tylenol).
A slightly warm bath or warm, damp washcloths on your forehead and wrists may ease your chills and body aches.
Health Solutions From Our Sponsors
Dall L., Stanford J.F. Clinical Methods: The History, Physical, and Laboratory Examinations, Butterworth Publishers, 1990.
Family Doctor: "Hyperthyroidism."
Family Doctor: "What are heat exhaustion and heatstroke?"
Gastroenterology: "Inflammatory Bowel Disease Clinical Presentation."
Harvard Health Publishing: "Treating fever in adults."
HealthPages: "Fever Symptoms in Adults."
Medical News Today: "Fever: what you need to know."
Medical News Today: "Why does my body ache?"
Medline Plus: "Fever."
MyMed.com: "Common causes and types of fever."