Can Allergies Turn Into a Sinus Infection?

You probably know the dreaded signs of seasonal allergies: Itchy, water eyes. A scratchy throat. And constant postnasal drip. You may even experience allergy symptoms once in a while. For example, they may appear during certain times of year. Or you can get them when you’re exposed to things like pet dander or smoke. But for some people, allergies can be a constant problem. 

If you suffer from allergies, you may wonder if your symptoms can turn into a sinus infection. Let’s take a closer look at how allergies can increase the risk of developing a sinus infection. 

Can allergies cause sinus infections?

Allergies don’t directly cause sinus infections. But they can increase your risk of developing a sinus infection. 

Normally, the tissue in your nasal passages and sinuses produces mucus. This mucus flows out toward your throat. Along the way, it carries any bacteria, viruses, and debris. This keeps your nasal passages and sinuses clear.

But allergies cause tissue swelling in the sinuses and nasal passages. If you have chronic allergies, the constant swelling of these tissues can put you at a higher risk for developing a viral or bacterial sinus infection. That’s because it’s easier for viruses or bacteria to get trapped in the swollen tissue. Once they’re trapped, they can multiply and cause an infection. 

What is the difference between allergies and a sinus infection?

Both allergies and a sinus infection can cause similar symptoms. But they’re different conditions and need different treatments.

An allergy develops when the immune system overreacts to an allergen, like pollen, smoke, or pet dander. A special protein antibody called immunoglobulin E (IgE) helps identify the presence of an allergen. IgE recruits other parts of the immune system to protect the nasal passages by releasing chemicals. The release of histamine and other inflammatory cells causes the symptoms of allergies. 

Sinus infections are when the sinus passages become infected with either a virus or bacteria. The immune system will identify the infection and begin to fight off the invading bug. During this process, fluid builds up in the sinus passages, causing pressure and pain. 

How do allergies turn into a sinus infection?

Allergies cause the nasal passages and sinuses to swell. If this swelling lasts for a long time, it can trap viruses or bacteria. Once trapped, these bugs have time to multiply and cause an infection. This is called a secondary or superimposed infection. This means you may start out with allergy symptoms and later develop symptoms of a sinus infection. 

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How are the symptoms of a sinus infection different from allergies?

Allergies and sinus infection share some symptoms, including:

• Cough

• Sinus congestion

• Sinus pressure

• Postnasal drip

Allergy symptoms

But they cause different symptoms too. Allergies are more likely to cause symptoms like:

• Itchy, water eyes

• Itchy throat

• Sneezing

• Bad breath

Sinus infection symptoms

Meanwhile, sinus infections are more likely to cause:

• Fever

• Green, yellow, or brown mucus

• Sinus pain

• Headaches

Symptom duration

How long symptoms last can also help distinguish between the two: 

• Sinus infections can last between 1 and 2 weeks. 

• Allergies typically last for as long as the trigger is present. This may be the entire spring or fall if you have seasonal allergies. Or it could be longer if you have year-round allergies.

Timing

Also, allergies and sinus infections can occur at the same time. Sinus infections usually develop on top of allergies. Often, people develop allergy symptoms first and then start to experience sinus infection symptoms a few weeks later. 

Can you stop allergies from turning into a sinus infection?

Yes, getting treatment for your allergies can lower your risk of developing a sinus infection. Allergy medications help decrease swelling in the sinuses. Over-the-counter allergy medications like intranasal steroids, anti-histamines, and decongestants can reduce allergy symptoms and decrease the chances of infection. 

What should you do if you think you have a sinus infection from allergies?

It’s best to seek care if you think you have a sinus infection. Sinus infections caused by bacteria should be treated with antibiotics. Your healthcare team can diagnose a sinus infection and start you on the right treatment. 

What increases the chances of allergies turning into a sinus infection?

Some factors can increase your chances of developing sinus infections. For example, you may be at higher risk of getting one if you: 

• Have a weakened immune system 

• Have changes that affect the shape of your nasal passages or sinuses, like a deviated septum

• Have had injuries to your face or facial surgery 

Physical changes to your face or sinuses can make it harder for the sinuses to drain, which increases the risk of bugs getting trapped in the sinuses. 

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Written by:

Meredith Grace Merkley, DO, FAAP

Meredith Grace Merkley, DO, FAAP, is a licensed, board-certified pediatrician with over a decade of work in community health. She serves as the medical director of a school-based health clinic at a federally funded health center.

Edited by:

Patricia Pinto-Garcia, MD, MPH

Patricia Pinto-Garcia, MD, MPH, is a medical editor at GoodRx. She is a licensed, board-certified pediatrician with more than a decade of experience in academic medicine.

Reviewed by:

Christine Giordano, MD

Christine Giordano, MD, is board-certified in general internal medicine. She received her medical degree from Rutgers New Jersey Medical School and completed residency at Thomas Jefferson University.

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