Healthy Living

Understanding Fever in Flu Season 2025

Oct. 8, 2025

Why You Have One and What To Do

There’s no getting around it—fevers are unpleasant. Still, the more you know about how they work, the better equipped you are to handle them next time you or a loved one gets sick.

Virtual Urgent Care provider Marque-Ann Mattle, PAC, explains what a fever is, why you might have one, and what to do if you have a fever this flu season.

What is a fever?

A fever is a body temperature that is higher than normal for you. The average body temperature for humans is 98.6°F, but it can vary from person to person. A typical range is between 97.5°F and 99.5°F, and this can change throughout the day and be a little higher in the afternoon and a little lower in the morning, for example.

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Most fevers are caused by illness. When you get a bacterial or viral infection, your body’s defenses kick in and your temperature rises as your immune system tries to kill off the invading germs. The higher body temperatures make your body a far more hostile environment to those viruses or bacteria, making it harder for them to survive.

Why do I have a fever?

Causes of fever can include:

White and blue thermometer for checking fevers

Chronic health conditions. Illnesses such as cancers or autoimmune diseases can cause the body’s temperature to increase.
Intense activity. Your body temperature rises when you are active and should return to normal as you recover from your workout.
Heat stroke or heat exhaustion. If you experience a high fever along with any other symptoms of heat illness, seek medical attention immediately.
Bacterial or viral infections. Typically, the most frequent cause of fever are the common culprits, including the flu, COVID-19, and strep throat.
Reaction to certain medications. Some medications can interfere with your body’s normal temperature balance.
Some vaccines. Because your body is learning to fight the illness the vaccine is intended to guard against, you might spike a fever in the first day or two after you receive the vaccine.

If you have a fever, you may also experience symptoms such as:

Body aches
Chills
Headache
Hot, dry skin

Increased heart rate
Loss of appetite
Nausea and vomiting
Rash

When taking your temperature, oral and rectal thermometers are the most accurate, but ear and forehead thermometers are also good options.

How to treat a fever

Fevers due to illness typically last three or four days, and they can often be managed at home. Ways to safely treat a fever at home include:

man in bed with fever holding thermometer and reading his temperature.

Drink plenty of fluids.
Rest as much as possible.
Take a lukewarm bath (around 98°F).
Use a cool, wet washcloth on your forehead, wrists, or the back of your neck.
Use nonsteroidal anti-inflammatory drugs such as ibuprofen or naproxen.
Painkillers like acetaminophen, or cold/cough medicine like DayQuil or NyQuil.

Common myths about fevers

Common misconceptions about fever include:

MYTH: Any oral temperature above 98.6°F is a fever.

A normal temperature is actually a range, and as an adult, your temperature is only considered a fever when it hits 100.4°F or above.

MYTH: You should always treat a fever with medication.

Medication is typically used to relieve discomfort associated with fever, not to break the fever itself. As an adult, if your fever is not causing you discomfort, you don’t necessarily need to take medication. You should, however, continue to monitor the fever.

MYTH: You should "starve a fever and feed a cold".

You should feed both. Your body needs energy to fight the illness, so stay hydrated and eat foods that are rich in nutrients. A fever might decrease your appetite, but it’s still important to eat small meals throughout the day to not overload your system. Drinking plenty of fluids can also help bring your temperature down and keep you from getting dehydrated.

Get care now, wherever you are

Make an appointment with your healthcare provider if:

You are having trouble breathing or urinating.
You have a fever over 103°F or higher.
Your fever has lasted longer than three days.
Your fever isn’t going down with the use of ibuprofen or acetaminophen.

Seeking medical care for fever is also a good idea if you don’t feel comfortable managing it at home or if you have unanswered questions. Always contact your healthcare provider if you have a fever and you have recently had surgery, are immunocompromised, or have recently traveled somewhere where a serious infectious disease is common.

Seek emergency medical care immediately if you experience a high fever with heat illness symptoms or if your fever is accompanied by symptoms such as seizure, lethargy, stiff neck, rash, or confusion.

Virtual Urgent Care

Have a fever but don’t want to wait in line at urgent care? Get care now with our Virtual Urgent Care. Note: You may be asked to come in for diagnostic tests if the online provider you see determines that your fever could be caused by an illness like COVID-19 or the flu.

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