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If you have symptoms like sneezing, chills, and fever, you may wonder if it’s allergies or an infection like a cold, flu, or COVID. Sometimes, telling the difference isn’t easy.

If you have these symptoms during the spring or fall and also have a temperature, you may wonder, “Can allergies cause fever? Can seasonal allergies cause fever?” Understanding these common illnesses can help you figure out what’s going on.

Can Allergies Cause Fever and Chills?

In general, allergies don’t cause a fever.

You can, however, have a fever at the same time as your seasonal allergies. But that doesn’t mean your seasonal allergies are causing your fever. Chances are something else is going on.

But can a child have a low-grade fever with allergies?

Children with allergies don’t typically have a low-grade fever as a symptom. If a child has a low-grade fever and allergy symptoms, it’s likely due to a concurrent viral infection.

On the other hand, can allergic reactions cause low body temperature?

Allergic reactions don’t usually cause a low body temperature. They most often lead to symptoms like hives, itching, and swelling but not changes in body temperature.

The same is true for chills. Allergies generally don’t cause chills. Chills are a common symptom of infections or illnesses that prompt the immune system to fight off pathogens.

These can include the flu or a cold. Chills typically come with a fever as the body tries to warm itself up to fight off an infection.

Differences Between Allergies, Colds, and the Flu — Which Cause Fever?

Allergies, colds, and influenza share some of the same symptoms. But different things cause each of these illnesses. Here’s how to tell them apart.

Seasonal allergies

According to the Centers for Disease Control and Prevention (CDC), more than one out of four U.S. adults and children have at least one allergy. Seasonal allergies are the most common type, affecting almost 26% of adults and nearly 19% of children.

What are allergies?

Allergies are when your body’s immune system considers certain substances a threat and overreacts to them. Allergic rhinitis is the medical term for nasal symptoms caused by allergies. You can also have food allergies or allergic skin reactions, though these aren’t typically seasonal.

You may have heard these symptoms referred to as hay fever. That’s the common term for allergic rhinitis.

This term may confuse you. Whether it’s allergic rhinitis or hay fever, you don’t need a sensitivity to hay to have allergy symptoms. Hay fever also doesn’t cause a fever.

Types of allergic rhinitis

Seasonal allergies, also called seasonal allergic rhinitis, are most common in spring and fall. Common seasonal allergy triggers or allergens are airborne mold spores and pollen from trees, grasses, and weeds.

Some people have allergic rhinitis year-round. The term for this is perennial allergic rhinitis. It’s often a reaction to indoor allergens, including cockroaches, dust mites, and pet dander.

Symptoms of allergic rhinitis

Allergies, including seasonal allergies, aren’t contagious. If you have seasonal allergies, you can’t spread them to or catch them from someone else. Fever isn’t a normal symptom of allergic rhinitis.

Common symptoms of allergic rhinitis include:

• Itchy, red, or watery eyes and puffy or swollen eyelids.
• Postnasal drip in the back of your throat. This can cause a sore throat.
• Runny nose, sneezing, and stuffy nose (congestion).
• Tiredness or fatigue. You may not sleep well because of congestion.

Common colds

Colds are common illnesses caused by viruses. According to the CDC, adults get two or three colds each year on average, while children have more.

You can get a cold when a respiratory virus attacks your immune system. Respiratory viruses spread when an infected person coughs or sneezes.

Several types of respiratory viruses cause colds. According to the CDC, rhinoviruses are the main cause of the common cold.

Common cold symptoms

As your body tries to fight off the virus, you develop symptoms.

These symptoms include:

• Body aches.
• Coughing.
• Headache.
• Fatigue.
• Fever.
• Nasal congestion.
• Sneezing.
• Sore throat, often from postnasal drip.
• Runny nose.

You can develop a cold anytime of year. Most colds last about seven days. But sometimes, your cold may take up to two weeks to go away.

The viruses that cause colds are contagious. You can catch a cold by breathing in virus droplets from someone who’s sick. You can also catch a cold by touching contaminated surfaces and then touching your eyes, nose, or mouth.

Influenza (aka the flu)

Influenza (flu) viruses can infect your nose, throat, and sometimes lungs. According to the CDC, about 8% of Americans get the flu in any given year. In some cases, it can result in death.

Flu season activity varies from year to year. In general, flu season lasts from October to May. Some years, flu season may start earlier. During other years, it may last longer.

An annual flu vaccine is the best way to prevent flu and reduce severe symptoms. The CDC recommends getting your yearly flu vaccine by the end of October for the most protection.

Flu symptoms

Unlike colds, flu symptoms come on suddenly. Fever is often a common sign during the first stage of the flu, but not everyone with the flu will get a fever.

Fevers caused by colds are often mild or low-grade. Fevers caused by the influenza virus are often higher in temperature and more severe.

Other common flu symptoms include:

• Body aches and pains.
• Cough.
• Chills or feeling feverish.
• Headaches.
• Fatigue or tiredness. You may sleep more than usual.
• Sore throat.
• Runny or stuffy nose.
• Sweating.
• Vomiting or diarrhea. These symptoms are more common in children than adults.

COVID-19

Even though the worldwide COVID-19 pandemic is officially over, you can still get COVID-19. So, what should you know about the differences between allergies and COVID-19?

COVID-19 is a respiratory illness. Infection with a coronavirus called SARS-CoV-2 causes COVID-19. Unlike seasonal allergies, COVID-19 is highly contagious.

Symptoms of COVID-19

Different people will develop different COVID-19 symptoms. You may have mild or severe symptoms. They often appear two to 14 days after exposure to the virus.

Common symptoms of COVID-19 include:

• Cough.
• Congestion or runny nose.
• Diarrhea.
• Difficulty breathing or shortness of breath.
• Fatigue.
• Fever or chills.
• Headache.
• Loss of taste or smell.
• Nausea or vomiting.
• Sore throat.

What Else Should You Know?

Having the flu, a common cold, or COVID-19 at the same time as seasonal allergies is possible. If you have a fever or other non-allergy symptoms (like a headache, vomiting, or chills), you may have an infection.

If you have signs of influenza or COVID-19, a simple test can tell you if you have either disease. If you do, you should stay away from other people to avoid spreading the infection.

If you have seasonal allergy symptoms, no infection symptoms, and your symptoms last longer than a couple of weeks, contact your doctor. They can refer you to an allergist. This is a doctor who specializes in diagnosing and treating allergies.

The allergist will run some allergy tests to see if you have allergies — and if so, what’s causing them. They’ll walk you through treatment options, including over-the-counter and prescription seasonal allergy medications and immunotherapy.

Editor's Note: This article was originally published on September 12, 2023, and was last reviewed on February 4, 2025.