Sinus Infection (Sinusitis): Causes, Symptoms & Treatment

Instructor: Danielle Haak

Danielle has a PhD in Natural Resource Sciences and a MSc in Biological Sciences

Many of us have experienced a sinus infection before, and I think we can all agree they aren't fun. Read this lesson to brush up on the causes, symptoms, and possible treatment options for sinus infections (also called sinusitis).

What is a Sinus Infection?

A sinus infection (also called sinusitis) is when the sinuses become filled with gunk (bacteria, viruses, fungi) and become blocked, causing a great deal of discomfort and gross side effects. Your sinuses are located behind the cheekbones, nose, forehead and eyes, and on either side of the bridge of the nose. Normally, healthy sinuses are filled with air only, so anytime there is a buildup of stuff that leads to an infection, you can imagine it will not be pleasant. Sinus infections are common; about 37 million Americans are diagnosed with sinus infections each year.

A sinus infection can occur in any of the sinuses, shown here.
sinus locations

Types of Sinus Infections

The types of sinus infections include acute, subacute, chronic and recurrent. In an acute infection, symptoms appear suddenly (facial pain, swelling, pressure), last longer than 10-14 days and disappear within 4 weeks. Subacute infections have the same symptoms, but they last between 4-8 weeks, while a chronic infection lasts more than 8 weeks, yikes! A person with recurrent sinusitis develops symptoms multiple times a year, as if one wasn't bad enough.

Causes of Sinus Infections

Your sinuses are more likely to become infected if you are already sick with a respiratory condition, like the common cold. People with nasal polyps, taking certain medications, and structural deformities are all more likely to develop sinus infections too. You can also get sinusitis from environmental factors, like allergies, or smoking. The sinuses can become infected due to a bacterial, viral, or fungal infection.


Let's face it, sinus infections are gross. If you have one, you might feel pain or pressure in the parts of your face with sinuses. It can actually make your head throb. The nose become stuffed up and might run, and this discharge might be colored a yellow or greenish color. This can also cause a cough and sore throat, as your nose drains into your throat. You'll also probably lose your sense of smell during the duration of the infection. Less common symptoms include bad breath, fatigue, a fever, and pain in the teeth.

Chronic sinus infections come with the joy of a few additional symptoms. You might experience pus in the nasal cavity and a complete blockage in the nose (nothing's moving). Obviously, this also increases the amount of pressure and pain associated with the infection.

Treatment Options

So, how is a sinus infection treated? Obviously, you want it to go away as soon as possible. Acute sinus infections can be treated with antibiotics (if applicable) or with over-the-counter decongestants. Steam inhalations can help treat symptoms as well. Chronic sinus infections are treated in similar ways. Additionally, warm compresses and humidifiers may help with symptoms.

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