Can Allergies Cause a Fever? An Immunology Expert Responds

Wondering if allergies can cause a fever? When the symptoms of allergies seem so similar to an infection, like COVID or a cold, it can be tough to differentiate between seasonal allergies and a virus…especially when your head’s a little foggy.

The Healthy by Reader’s Digest asked Dr. Andrea Burke, MD, a New York City-based board-certified allergist and immunologist, whether allergies can cause a fever—and what triggers a fever response in the body.

Common allergy symptoms

Allergy symptoms typically include:

• sneezing
• nasal congestion
• watery and itchy eyes
• coughing
• trouble breathing due to congestion

But what about fevers?

Can allergies cause a fever?

According to Dr. Burke, the answer is: no, allergies can not cause a fever. “Fever is a response of the immune system that is triggered by an infection,” she says.

Fever is the body’s natural, biological response when it’s working to kill off an infection. The body’s temperature rises because the infection is able to thrive at a normal temperature—but at a higher temperature, it is harder for the infection to survive.

Burke also points out that a fever triggers the immune system for other types of inflammatory conditions besides infections, such as Crohn’s disease and rheumatoid arthritis. “These two things cause an inflammatory response, and the infection is a different response from the allergic immune system,” Burke explains. “High level, your immune system is very complex and it has a bunch of different cells involved in fighting infection. The allergy cells are still part of the family of the immune system.” But, she says: “When they are activated, they do not activate a fever response.”

You’re probably dealing with an infection instead

Because many of the symptoms of allergies and viral infections seem similar, Burke says it can easily be confusing to differentiate which response your body is experiencing. A fever can be an easy indicator to help you distinguish that you are dealing with a viral or bacterial infection, instead of allergies.

Another clear indicator between differentiating allergies and infection is dealing with itchiness and sneezing. “Itchiness and sneezing are more allergies, and the infection-fighting response releases [other symptoms] that trigger fever,” Dr. Burke explains.

However, allergies can lead to sinus infections, which can cause a fever

If a person is dealing with a sinus infection, even one brought on by allergies, it’s possible they’ll experience a fever.

Dr. Burke says, “Some people who can get really bad allergies that could get a sinus infection and their sinuses can’t drain, so they may get a secondary sinus infection and the allergies triggered it and gave them a fever.”

According to the American College of Allergy, Asthma and Immunology, sinus infections are bacterial and can result in symptoms such as:

• headache or facial pain
• runny nose or nasal congestion
• coughing
• fever

However, given that a fever is triggered due to a bacterial infection, it’s still holds true that allergies alone can’t cause a fever.

For daily wellness updates, subscribe to The Healthy by Reader’s Digest newsletter and follow The Healthy on Facebook and Instagram. Keep reading:

• 6 Clear Signs You’re Getting Sick
• 11 Best Foods for Your Immune System
• 20 Bizarre Things You Didn’t Know You Could Be Allergic To