Are Sinus Infections Contagious?

Viral sinus infections are contagious because they develop from colds or flu viruses that spread between people. However, sinus infections caused by bacteria, allergies, or structural problems in the nose are not contagious. Identifying the cause helps determine whether you can pass it on and how to treat it.

Are Sinus Infections Contagious?

Medically Reviewed

By

Chrysoula I. Liakou

MD, PhD, Internal Medicine Specialist and Cancer Immunology Researcher.

Are sinus infections contagious?

Viral sinus infections are contagious because they stem from colds or flu, which can spread to others. However, sinus infections caused by bacteria or allergies are not contagious.

 

Are Sinus Infections Contagious or Not?

It varies depending on the type of infection you have. Viruses, bacteria, and allergies cause sinusitis. A virus like a cold or influenza is the most common infection. You are contagious when you have a sinus infection caused by one of these illnesses.


The only illness you can transmit directly is the cold or influenza virus that caused your sinus infection, not the sinus infection itself. Not everyone who gets the virus from you will get a sinus infection; they may get a cold or flu. Sinus infections caused by bacteria or allergies are not contagious.


A bacterial sinus infection occurs when the nasal passages are blocked for a prolonged period, which allows bacteria to grow. Allergies can cause chronic sinusitis in some cases. Both of these cannot be passed on to others. Most sinus infections are viral; if you have symptoms for less than two weeks, they will disappear.


In most cases, bacterial sinusitis develops as a complication of viral sinusitis. By exploring what sinus infections are, what causes them, and how they spread, we will learn how to distinguish between their three leading causes. Afterwards, I will discuss common sinus infections and when to see a doctor.


What Exactly Is a Sinus Infection?

The sinuses surround a person's nasal and facial passages and humidify outside air before reaching the lungs. They can be found on the forehead, cheekbones, and behind the nose.


Inflammation of the sinus passages can occur from viral respiratory infections, such as colds, or external irritations, such as allergens, pollution, or cigarette smoke.


Inflamed sinuses drain mucus more slowly. Due to this, sinus infections cause pain, pressure, and other symptoms. The pooled mucous can grow bacteria over time, resulting in bacterial sinusitis.


The following symptoms characterise sinus infections:

  • Postnasal drip

  • Having congestion

  • A feeling of pain or swelling in the cheeks or forehead

  • Sore throat

  • Toothache

  • Bad breath

  • Consistent cough

  • Fatigue

  • Fever

  • Having a runny nose or nasal discharge that looks green or yellow



What Triggers a Sinus Infection?

Sinusitis is most commonly caused by the cold, which causes swelling and irritation in the sinuses.


Infections of the sinuses can also be contracted through:

  • Nasal growths that may be asymptomatic but block sinus passageways

  • A deviated septum or previous sinus or nose surgery can structurally alter the nasal cavity.

  • In common allergy seasons, hay fever (seasonal allergies or allergic rhinitis) causes swelling in the nose.


Even though sinus infections are common, and most adults will experience one at some point, external factors can make sinus infections more prevalent.


You are more likely to develop a sinus infection if you have the following risk factors:

  • A long-lasting cold

  • Smoking or being exposed to secondhand smoke

  • Sinus problems such as a broken nose

  • Taking a new drug that weakens the immune system or having a weak immunity system.



How Do Sinus Infections Spread?

Sinusitis usually spreads in the same way a cold or flu does. Particles and droplets carrying viruses become airborne after a person coughs or sneezes, and those viruses then transfer to others.


These viruses can also be transmitted by body touch. Surfaces like doorknobs can become a reservoir for a virus if a sick person touches them before a healthy person does. That's why cleaning your hands with soap and water, protecting your mouth when you cough or sneeze, and staying away from close encounters with infected people are essential in preventing getting sick.


But even with the utmost stringent measures, sinusitis is standard enough that illnesses still spread quickly. How long are sinus infections contagious? Generally, when caused by a viral infection, a person will usually experience symptoms for 7-10 days.


In these cases, they will be infected with the main virus for two weeks, from a few days before they have symptoms until after the illnesses are gone.


Allergic sinusitis and bacterial sinus infections that arise after a virus are not infectious to others. 

 

Types of Sinus Infections and Contagiousness
Type of Sinusitis Cause Contagious?
Viral Sinusitis Cold or flu viruses Yes
Bacterial Sinusitis Bacterial overgrowth No
Allergic Sinusitis Allergens (e.g. pollen) No



How to Treat a Sinus Infection at Home

It is fortunate most sinus infections disappear without needing any prescription medication.


The majority will react well to over-the-counter treatments with time. Nearly 50% of cases without antibiotics get better within a week, and 70% resolve in two weeks.


There are various ways to ease and speed up this process with home remedies while easing pressure and pain from the sinuses:

  • Apply a warm compress: Apply it to the forehead and nose.

  • Decongestant nasal sprays can help drain and dry up the pooled mucous. As long as you're experiencing symptoms, take oxymetazoline (Afrin) twice daily for three days only (avoid if you are suffering from high BP) or fluticasone (Flonase) twice daily.

  • Nasal sprays and saline rinses can help thin and clear pooled mucous, preventing bacterial infection and relieving symptoms. These can be used several times a day.

  • Inhaling steam: A warm shower or a bowl can be used.

  • Polluted air, cigarette smoke, and anything else that contains air contaminants can irritate and inflame the lungs.

  • Using a humidifier: Humidifiers can provide relief by adding moisture to the air.

  • Do rest and drink plenty of water.

  • A nasal decongestant over the counter can provide temporary relief but should not be used for more than three consecutive days.

  • You can treat sinus headaches and discomfort by taking acetaminophen or ibuprofen with or without a decongestant.

  • When taking Robitussin or Mucinex, look for the active ingredient guaifenesin. Mucus can be thinned, and coughing can be reduced with these medicines.



When Should You See a Doctor for a Sinus Infection?

Most sinus infections will resolve independently without antibiotics, but some patients will require antibiotics or other solutions prescribed by their healthcare provider.


Whenever you are experiencing one or more of the below symptoms, you should seek medical attention:

  • Ibuprofen, acetaminophen, and decongestants do not relieve severe headaches or intense facial pain

  • After initial improvement, symptoms get worse

  • Symptoms that persist for more than ten days without improvement

  • A fever that persists for more than three days over 100.4°F

  • A fever of more than 102°F (38.8°C)

  • Double vision, severe swelling, redness around the eyes, or problems seeing.

  • Over a year, multiple sinus infections.

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FAQs About Sinus Infections

How long are sinus infections contagious?
Viral sinus infections are usually contagious for about 7–10 days. You're typically infectious a couple of days before symptoms appear and until they resolve.

Is a sinus infection the same as a cold?
No. A cold can lead to a sinus infection, but sinusitis involves inflammation and blockage of the sinus cavities, often with facial pain and pressure.

Can I go to work with a sinus infection?
If your sinus infection is viral and you're still contagious, it’s best to stay home until your fever is gone and symptoms improve. Bacterial and allergic sinusitis are not contagious.

Do I need antibiotics for a sinus infection?
Not always. Most sinus infections are viral and clear up on their own. Antibiotics are only needed for bacterial infections that last longer than 10 days or worsen.

Can Mobi Doctor help with sinus infections?
Yes. With Mobi Doctor, you can consult an online GP, get diagnosed, and receive prescriptions for sinus infection treatment—without leaving your home.

 

What Mobi Doctor Can Do For You

Mobi Doctor offers online urgent care. In minutes, you can check your symptoms, research conditions and treatments, and text a healthcare provider if needed.

Mobi Doctor is a virtual clinic that provides online consultations and 24/7 support for people with health problems. You can talk to our experts about any health problem, whether an infection, an injury, or a mental health issue. We offer tailored advice and support from our team of doctors and experts.


With Mobi Doctor, you get online urgent care.



FAQ

Viral sinus infections are contagious for about 7–10 days—from a couple of days before symptoms start until they clear. Bacterial and allergic sinus infections are not contagious.

You can’t directly transmit the sinus infection itself, but you can spread the cold or flu virus that caused it. The other person may develop a cold, not necessarily sinusitis.

Not usually. Most sinus infections are viral and resolve on their own. Antibiotics are only needed for bacterial infections lasting longer than 10 days or worsening after initial improvement.

If your infection is viral and you have fever or active symptoms, stay home until you feel better to avoid spreading germs. Once fever-free for 24 hours and symptoms improve, it’s safe to return.

Wash your hands often, manage allergies, avoid smoking, and use a humidifier in dry environments. Staying hydrated and treating colds early can also prevent sinus blockage and infection.


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