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If you have symptoms like sneezing, chills, and fever, you may wonder if it’s allergies, a cold, or the flu. Sometimes it’s not easy to tell the difference among these illnesses.

If you have these symptoms during the spring or fall and also have a temperature, you may wonder, do allergies cause fever? Or can you have allergies and a viral infection at the same? Understanding what causes each of these illnesses can help you figure out what’s going on.

Can Allergies Cause a Fever?

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 that is causing your fever.

Difference Between Allergies, Colds, and the Flu

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

Seasonal allergies

More than one out of four U.S. adults and children have at least one allergy, according to the Centers for Disease Control and Prevention. Seasonal allergies are the most common type of allergy. They affect nearly 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 may have heard it called hay fever. That’s the common term for allergic rhinitis.

It’s understandable if this term confuses you. Whether it’s called 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, according to the American College of Allergy, Asthma & Immunology.

Types of allergic rhinitis

Seasonal allergies are also called seasonal allergic rhinitis. The most common times for seasonal allergies are 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. This is called 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, are not contagious. If you have seasonal allergies, you can’t spread them to or catch them from someone else. Fever is not a normal symptom of allergic rhinitis.

Common symptoms of allergic rhinitis include:

• Itchy, red, or watery eyes.
• Puffy or swollen eyelids.
• Runny nose and/or post-nasal drip in the back of your throat. This can cause a sore throat.
• Sneezing.
• Stuffy nose or congestion.
• Tiredness or fatigue. You may not sleep well because you are congested.

Common colds

Colds are a common illness. According to the CDC, each year adults get one cold on average. Children get two colds on average.

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

There are several types of respiratory viruses that cause colds. Rhinoviruses are the most common cause of the common cold, according to the CDC.

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 post-nasal drip.
• Runny nose.

You can develop a cold any time of year. Most colds last about seven days. But sometimes it can take up to two weeks for your cold to go away.

The viruses that cause colds are contagious. You can catch a cold by breathing in virus droplets from someone who is 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. On average, about 8% of people get the flu each year in the U.S., according to the CDC. In some people, the flu can lead to 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. Some years it may last longer.

Getting an annual flu vaccine is the best way to prevent flu and reduce severe symptoms. For the most protection, the CDC recommends getting your annual flu vaccine by the end of October.

Flu symptoms

Unlike colds, symptoms of the flu come on suddenly. During the first stage of the flu, fever is often a common sign. 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 more severe or higher.

Other common flu symptoms include:

• Body aches and pains.
• Cough.
• Chills or feeling feverish.
• Headaches.
• Fatigue or tiredness. You may sleep more than normal.
• 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 now 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 2 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.
• Headache.
• Loss of taste or smell.
• Nausea or vomiting.
• Sore throat.

What Else Should You Know?

It is possible to have the flu, a common cold, or COVID-19 at the same time as seasonal allergies. If you have a fever or any 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 have either of these diseases.

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 do allergy testing to see if you have allergies — and if so, what you’re allergic to.

Allergy treatments include:

• Over-the-counter and prescription seasonal allergy medications.
• Allergy immunotherapy. You will get or start this treatment at your doctor’s office. It includes allergy shots and sublingual immunotherapy (SLIT).