Are sinus infections contagious?

The sinuses or paranasal sinuses are four paired cavities or space, connected by narrow channels in the skull. The exact function of the paranasal sinuses is not well understood. But their possible roles may include reducing the weight of the skull, dampening pressure, humidifying and warming inspired air, absorbing heat and insulating the brain, aiding in sound resonance, providing mechanical rigidity, and increasing the olfactory surface area. The sinuses also make thin mucus that drains out of the channels of the nose. This drainage helps keep the nose clean and free of bacteria. They are normally filled with air. 

The four different types of sinuses and their locations are:

  • The ethmoidal sinuses which are located between the eyes.
  • The maxillary sinuses which are located below the eyes.
  • The sphenoidal sinuses which located behind the eyes, and
  • The frontal sinuses which are located above the eyes.

The maxillary cavity is the biggest sinus and, and it is one of the cavities that most often becomes infected.

What happens in sinus infections and how common are they?

Sinus infection occurs when there is inflammation of the lining of the sinuses. This inflammation leads to blockade of the normal sinus drainage pathways, which in turn leads to mucus retention, hypoxia or reduced oxygen availability, decreased clearance of mucus by the specialized cells in the sinuses (cilia), and predisposition to bacterial growth. These processes are responsible for the typical symptoms of sinus infections or sinusitis (rhino sinusitis).

According to research, Sinusitis or rhino sinusitis is one of the most common reasons for clinical visits in the United States. It is also one of the top reasons that antibiotics are prescribed. Over a one-year period, there were up to 73 million restricted-activity days related to sinusitis and total direct medical costs of almost 2.4 billion, not including surgery or radiographic imaging. In addition, up to 14.7 percent of individuals surveyed in the National Health Interview Survey reported having had sinusitis the preceding year.

The Cleveland clinic also states that when sinusitis is considered together with other commonly associated disease conditions such as allergic rhinitis, asthma, and chronic bronchitis, exacerbation of these diseases affects more than 90 million people, which is nearly one in three Americans.

 What are the causes and types of sinusitis?

Viruses are the commonest cause of sinusitis. The most frequently implicated viruses are rhino-, influenza, and para-influenza viruses. In a smaller amount of cases, bacteria can also cause sinusitis. Common causes of bacterial sinusitis are: Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, and Streptococcus pyogenes. Sinusitis can also be caused by allergies.

Sinusitis can be divided into the following categories based on the duration of symptoms. They are:

Acute sinusitis, defined as symptoms of less than 4 weeks’ duration

Subacute sinusitis, defined as symptoms of 4 to 8 weeks’ duration;

Chronic sinusitis, defined as symptoms lasting longer than 8 weeks

Recurrent acute sinusitis, often defined as three or more episodes per year, with each episode lasting less than 2 weeks.

What are the risk factors for sinus infection?

The commonest risk factor that predisposes a person to a sinus infection is common cold. The inflammation caused by a common cold may often predispose a person to developing a sinus infection. in such cases, an acute sinus infection will follow an episode of common cold.

Other risk factors for developing a sinus infection are: abnormalities in the structure of the nose, enlarged adenoids, diving and swimming, tooth infections, nose injury, foreign objects stuck in the nose, and secondhand smoking.

What are the symptoms of sinus infection?

The signs and symptoms of acute and chronic sinusitis are basically the same. The difference is mostly in the duration of the symptoms. These symptoms are:

Nasal inflammation

Thick, discolored discharge from the nose (runny nose)

Drainage down the back of the throat (postnasal drainage)

Blocked or stuffy (congested) nose causing difficulty breathing through the nose

Pain, tenderness and swelling around the eyes, cheeks, nose or forehead

Reduced sense of smell and taste

Ear pain



Aching in the upper jaw and teeth

Cough or throat clearing

Sore throat

Bad breath and


Is sinus infection contagious?

A sinus infection can be contagious depending on the cause of the infection. Just like most viral infections, sinus infections caused by a virus can be very contagious. Sinus infections caused by bacteria and allergies are however, not contagious. This information is important because most sinus infections are caused by viruses. A person with viral sinusitis may be contagious for just a few days, although it could linger for a week or more.

How Is a sinus infection spread?

A sinus infection is spread the same way a common cold is spread. This is by breathing in infected droplets (mostly from coughing and sneezing) from being close to an infected person or contacting it from touching a surface already contaminated by the touch of an infected person containing the virus-laden respiratory secretion. They also can be passed on when someone shakes hands with someone who is sick or touches a doorknob or anything else the sick person has touched.

How do you prevent spread of a sinus infection?

To prevent the spread of a sinus infection, an infected person should avoid close contact with people when they are sick like hugging, kissing. They should stay at home and keep children out of school or daycare while they are sick. It is also important to move away from people before coughing or sneezing. Coughing and sneezing should be done into a tissue, and then flushed away, or into the upper shirt sleeve, or bend of the elbow, with the mouth and nose completely covered. Washing the hands after coughing, sneezing, or blowing the nose is also important to avoid spread of sinusitis.

To prevent contacting it, a person should also avoid close contact with an individual with sinusitis. They should wash the hands as often as possible with soap and clean water and avoid touching the face as much as possible.

Treatment of sinus infection

The treatment of a sinus infection depends on the level of severity of the infection. Simple home remedies like steam inhalation, rest, and hydration can be effective in mild cases. The infection usually resolves on its own in most cases caused by viruses.

In more serious cases, there may be need to visit the doctor who would recommend treatments to help relieve sinusitis symptoms, including: Saline nasal spray, nasal decongestants, nasal corticosteroids, antibiotics, cough medicines, antihistamines, Nonsteroidal anti-inflammatory drug and Analgesics.  In extreme cases, the sinus maybe surgically drained by the doctor after appropriate radiological investigations have been done.