What Is a Sinus Infection?

What Is a Sinus Infection?

A sinus infection happens when the tissue lining the sinuses becomes inflamed and swollen. Fluid builds up, providing a place for viruses and bacteria to grow. This causes an infection.

The sinuses are air-filled hollow spaces in the bones near the nose, cheeks, eyes, and forehead. Normally they produce a thin mucus that drains out through the nose. The mucus carries away germs. Inflammation from a cold or other irritant can block this cleansing process and trap viruses and bacteria.

Are sinus infections contagious?

Most sinus infections are caused by viruses. The viruses can be spread through sneezes and coughs. Bacterial and fungal sinusitis may be contagious as well.

Types of Sinus Infections


Doctors diagnose types of sinus infections based on how long they last. These types share many similar symptoms, but there are some differences as well.

  • Acute sinusitis. Acute means that sinus inflammation is short-term. Symptoms like runny nose, stuffy nose, and facial pain usually get better within ten days, but sometimes they last a few weeks. Symptoms of acute sinusitis may improve after a few days and then come back worse than they started.
  • Chronic sinusitis. With chronic, or long-term, sinusitis, the linings of the sinuses are swollen for 12 weeks or more. Symptoms of chronic sinusitis include nasal congestion, facial pain or pressure, and decreased sense of smell.
  • Subacute sinusitis. Swelling of the mucous membranes lasting between four and 12 weeks.
  • Allergic sinusitis. Allergic reactions to pollen, dust, and other irritants can inflame the sinus membranes, a condition sometimes called allergic rhinitis. This may lead to a sinus infection. Unlike other types of sinusitis, allergies also can cause itchy eyes, nose, or throat.
  • Recurrent sinusitis. Recurrent sinusitis goes away and comes back several times a year.

Signs & Symptoms of Sinus Infections


A primary care doctor can help determine whether symptoms are a sinus infection or something else, and identify the underlying cause of sinus inflammation. Your doctor also can advise on treatment and prescribe antibiotics if needed.

Symptoms of sinusitis, both acute (lasting 10 days to four weeks) and chronic (lasting 12 weeks or more) can include:

  • Runny nose
  • Congestion (stuffy nose)
  • Yellow or green discharge from nose
  • Post-nasal drip
  • Headache
  • Pain and pressure in the face
  • Cough
  • Tooth pain
  • Reduced sense of taste or smell
  • Bad breath
  • Fever
  • Fatigue

What Causes Sinus Infections?


Viruses cause most sinus infections. Less often, bacteria or fungi are to blame. The viruses that most commonly lead to sinus infections are:

Anyone can get a sinus infection. But the risk of getting sinusitis is higher if you have certain conditions or nose structures, including:

  • Allergies (seasonal, dust mites, animal dander)
  • Nasal polyps (growths inside the nose)
  • Deviated septum (structure inside the nose)
  • Immune system weakened by illness or medication
  • Smoking

How to Prevent Sinus Infections


Whether you are healthy or already have a cold, you can take these steps to prevent sinusitis:

  • Wash your hands frequently
  • Avoid being around people who have colds or other infections
  • Drink plenty of water to keep mucus thin
  • Keep allergies in control
  • Avoid cigarette smoke

If you already have cold symptoms, you can:

  • Use a steroid nasal spray for congestion, if recommended by your doctor
  • Use a salt water (saline) spray to keep the nose moist
  • Rinse your nose with salt water
Get Care

Trust NewYork-Presbyterian for Sinus Infection Care

Schedule an appointment or video visit with NewYork-Presbyterian at a convenient medical group location to see a doctor and find out if you have a sinus infection.

Our primary care doctors are available for same-day appointments for critical needs such as serious upper respiratory infections, and easy scheduling with early, late, and weekend hours. We accept most insurance. When you have a sinus infection, it’s important to know your treatment options.