Are Sinus Infections Contagious?

Turns out, it depends on what's causing your sinusitis. Here's what to know.

Even though sinus infections are often caused by contagious organisms like viruses and bacteria, experts are not completely agreed on whether the infections themselves can be spread.

Part of the confusion lies in the fact that sinus infections can be caused by so many different things. “A sinus infection can be caused by viruses or bacteria that cause inflammation where the sinuses drain into the nose,” explains Lisa Liberatore, MD, an ear, nose, and throat specialist at Lenox Hill Hospital in New York City.

The sinuses are a series of bony cavities in your skull designed to keep foreign particles like dust and germs out of your body. They’re lined with mucus to trap those particles; then, little hair-like projections called cilia sweep back to front to jettison the invaders from your body.

But inflammation can cause the mucus to get trapped, Dr. Liberatore says, and then germs can grow, which can lead to a sinus infection, or sinusitis.

Anything that can cause your sinuses to narrow or get blocked can also cause sinusitis. Most acute sinus infections (those that last only seven to 10 days) are caused by viruses. But bacteria and fungi are also sometimes culprits. Meanwhile, people with chronic sinusitis (infections that last longer than 10 days and/or recur) can have risk factors like nasal polyps, allergies, immune system problems, and anatomical features like a deviated septum.

Whether or not a sinus infection is contagious can depend on the underlying cause. “Allergies, inflammatory conditions, and other issues leading to inflammation can result in all the symptoms of a sinus infection without the contagious component,” says Noah Stern, MD, program director of otolaryngology at Detroit Medical Center’s Harper University and Hutzel Women’s and Detroit Receiving Hospitals.

Other causes, especially viruses, are transmissible. “The viral pathogens are the same as those that cause the common cold,” Dr. Stern explains. Rhinoviruses are common viral causes of both colds and sinus infections.

Droplets of virus that spread through the air or are transferred by hand contact can pass the germ to someone else. That unsuspecting person is more likely to come down with a cold, if that happens—but the cold could morph into a sinus infection.

While a quick internet search turns up claims that bacterial sinusitis is not infectious, that may not be entirely true, according to Dr. Stern. “The bacterial pathogens behave like other infectious bacteria and can be spread.”

How to stop the spread

You can prevent spreading sinus infections the same way you would prevent passing along a cold or the flu.

“Good hand hygiene is sufficient to dramatically decrease the spread,” says Dr. Stern. “One should wash their hands after touching or blowing their nose and prior to contacting objects or others to decrease the likelihood of transmission.”

Dr. Stern also recommends nasal irrigation with a saline solution. That, he says, is the nasal equivalent of hand-washing.

It also keeps your nasal passages moist, which will help prevent sinusitis. Other ways to do this include using nasal spray throughout the day, using a humidifier at home (especially in your bedroom), drinking plenty of water, inhaling steam (try a long hot shower), and sleeping with your head elevated to prevent mucus from collecting in your sinuses.

Also make sure you’re up to date on your vaccinations, especially the annual flu shot. The influenza virus can also lead to sinus infections.

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