What is sinusitis?

Sinusitis is an inflammation, or swelling, of the tissue lining the sinuses. The sinuses are four paired cavities (spaces) in the head. They are connected by narrow channels. The sinuses make thin mucus that drains out of the channels of the nose. This drainage helps keep the nose clean and free of bacteria. Normally filled with air, the sinuses can get blocked and filled with fluid. When that happens, bacteria can grow and cause an infection (bacterial sinusitis).

This is also called rhinosinusitis, with “rhino” meaning “nose.” The nasal tissue is almost always swollen if sinus tissue is inflamed.

What are the different types of sinuses near the nose and eyes?

The paranasal sinuses are located in your head near your nose and eyes. They are named after the bones that provide their structure.

  • The ethmoidal sinuses are located between your eyes.
  • The maxillary sinuses are located below your eyes.
  • The sphenoidal sinuses are located behind your eyes.
  • The frontal sinuses are located above your eyes.

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

There are different types of sinusitis:

  • Acute bacterial sinusitis: This term refers to a sudden onset of cold symptoms such as runny nose, stuffy nose, and facial pain that does not go away after 10 days, or symptoms that seem to improve but then return and are worse than the initial symptoms (termed “double sickening”). It responds well to antibiotics and decongestants.
  • Chronic sinusitis: This term refers to a condition defined by nasal congestion, drainage, facial pain/pressure, and decreased sense of smell for at least 12 weeks.
  • Subacute sinusitis: This term is used when the symptoms last four to twelve weeks.
  • Recurrent acute sinusitis: This term is used when the symptoms come back four or more times in one year and last less than two weeks each time.

Who gets sinusitis?

A sinus infection can happen to anyone. However, people with nasal allergies, nasal polyps, asthma and abnormal nose structures are all more likely to get sinusitis. Smoking can also increase how often you get a sinus infection.

There are an estimated 31 million people in the United States with sinusitis.

How can I tell if I have a sinus infection, cold, or nasal allergy?

It can be difficult to tell the difference between a cold, allergies, and a sinus infection. The common cold typically builds, peaks, and slowly disappears. It lasts a few days to a week. A cold can transform into a sinus infection. Nasal allergy is inflammation of the nose due to irritating particles (dust, pollen, and dander). Symptoms of a nasal allergy can include sneezing, itchy nose and eyes, congestion, runny nose, and post nasal drip (mucus in the throat). Sinusitis and allergy symptoms can happen at the same time as a common cold.

If you are fighting off a cold and develop symptoms of a sinus infection or nasal allergy, see your healthcare provider. You will be asked to describe your symptoms and medical history.

What causes sinusitis?

Sinusitis can be caused by a virus, bacteria, or fungus that swells and blocks the sinuses. A few specific causes include:

  • The common cold.
  • Nasal and seasonal allergies, including allergies to mold.
  • Polyps (growths).
  • A deviated septum. The septum is the line of cartilage that divides your nose. A deviated septum means that it isn’t straight, so that it is closer to the nasal passage on one side of your nose, causing a blockage.
  • A weak immune system from illness or medications.

For infants and young children, spending time in day cares, using pacifiers or drinking bottles while lying down could increase the chances of getting sinusitis.

For adults, smoking increases the risks for sinus infections. If you smoke, you should stop. Smoking is harmful to you and to the people around you.

Is sinusitis contagious?

You can’t spread bacterial sinusitis, but you can spread viruses that lead to sinusitis. Remember to follow good hand washing practices, to avoid people if you are sick and to sneeze or cough into your elbow if you have to sneeze or cough.

What are the signs and symptoms of sinusitis?

Common signs and symptoms of sinusitis include:

  • Post nasal drip (mucus drips down the throat).
  • Nasal discharge (thick yellow or green discharge from nose) or stuffy nose
  • Facial pressure (particularly around the nose, eyes, and forehead), headache and or pain in your teeth or ears.
  • Halitosis (bad breath)
  • Cough.
  • Tiredness.
  • Fever.

##

Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy