How Do I Know if I Have Sinusitis?

Written by Nichole Owens
Medically Reviewed by Zilpah Sheikh, MD on March 24, 2025
5 min read

The common cold and sinusitis share many of the same symptoms, but they differ in how long the symptoms last and certain patterns.

You know the signs of a common cold — stuffy or runny nose, sore throat, sneezing, and general misery. These usually clear up in a week or so, and you’re back to normal. 

Sinusitis, also known as a sinus infection, is an inflammation or swelling of your sinuses, usually caused by a virus or bacterial infection , or sometimes fungus .

Sinus infections tend to linger longer than colds. “One of the most telling signs of bacterial sinusitis is double-worsening, where cold symptoms initially improve but then worsen after a few days,” says Mostafa Ahmed, MD, board-certified otolaryngologist at the Centers for Advanced ENT Care in Maryland. 

Most cases of sinusitis are “acute,” which means they come on suddenly and last less than eight weeks. Symptoms of sinusitis include congestion that makes it hard to breathe through your nose, and tenderness around your nose and eyes. 

Other signs you might have a sinus infection include:

  • Symptoms last longer than 10 days without getting better
  • Pain or pressure around your forehead, cheeks, nose, or between your eyes
  • Mucus draining down your throat
  • Sore throat, bad breath, or cough that won’t go away
  • Fever above 100.4 F
  • Feeling of fullness in your ears

You may also think you have a toothache when it’s really a sinus infection. Your upper back teeth are very close to your sinuses, so tooth pain (and facial pain) is a very common symptom of a sinus infection. If you’re not sure, check with your doctor or dentist.

If you have any of these symptoms and over-the-counter treatments don’t help, call your doctor. You may need a doctor to diagnose chronic sinusitis, and it may require more treatment than acute sinusitis.

Contact your doctor right away if you have any of these severe symptoms, as they could be signal a serious infection:

Only your doctor can diagnose a sinus infection. Tell them how long you’ve had sinus symptoms, and whether they’ve gotten worse or stayed the same. This will help your doctor find out whether your sinus infection is caused by a virus or bacteria.

Viral sinusitis

If you’ve had sinus infection symptoms for 7-10 days and they’re not getting worse, you may have a viral infection. It will likely go away on its own.

Over-the-counter (OTC) treatments, such as saline rinses, may help clear mucus. Nasal corticosteroids such as fluticasone (Flonase) or mometasone (Nasonex) also may help reduce nasal swelling. OTC medicines, such as acetaminophen or ibuprofen, may help ease pain. Decongestants may reduce swelling, but use them for one to two days only. They can make you feel even stuffier and cause problems with high blood pressure.

Bacterial sinusitis

If you’ve been sick for 10 days or more with no improvement, or you got slightly better and then sicker, you may have a bacterial infection. Again, you’ll need to see your doctor to know for sure.

If it’s bacterial sinusitis, your doctor will likely prescribe you antibiotics to kill the bacteria. Your doctor may also recommend that you use saline rinses, OTC pain medicines, or decongestants to relieve your symptoms.

Your doctor will talk to you about your symptoms. They'll likely perform one of several tests to find out if you have a sinus infection. Here are some of the tests your doctor can use.

Nasal endoscopy

This is a quick and simple procedure that lets your doctor see inside your sinuses. Your doctor will give you a spray that contains a decongestant and medicine to numb your nose. Then, they’ll use a rigid telescope with a camera at the end to look inside your nose and sinuses. Your doctor may take a sample of your mucus or tissues for further testing.

Imaging tests

Sometimes, you may need to get a CT scan to look for more serious inflammation deep in your sinuses. A CT scan is a special X-ray that lets your doctor see detailed images of your sinuses. They can show your doctor if something is blocking your sinuses or if there's anything abnormal. CT scans aren't painful and take just a few minutes. 

Sinus and nasal culture

Your doctor may also take a swab, or nasal culture, from inside your sinuses if they think you may have a fungal or bacterial infection. Your doctor usually won't need a culture to diagnose sinusitis, but if you’re not getting better, these could help your doctor figure out why.

Skin allergy test

Sometimes, allergies can cause a sinus infection. If your doctor thinks your allergies may be the cause of your sinusitis, they can do a skin prick test or blood test to find out what’s causing your allergy and symptoms.

Blood tests

If your sinus infection symptoms get better but keep coming back, your doctor may order blood tests. The results can tell them if something else is going on with your immune system that could be causing your symptoms.

Once you have a definite diagnosis, you can start on a treatment plan that will relieve your symptoms and may even keep them from coming back.

Sinus infection, or sinusitis, is swelling of the tissues around the sinuses caused by a virus or bacteria. Sinus infections have similar symptoms as other ailments, such as the common cold or allergies. But what sets sinus infections apart is how long they last, often 10 days or more. 

There are a number of ways your doctor can test and treat a sinus infection, including blood tests and CT scans. If your symptoms get better but then return, worsen or last longer than 10 days, see your doctor. They can help you find the best treatment.

What other conditions can be mistaken for a sinus infection?

Upper respiratory infections and allergies can look a lot like sinus infection. What often sets them apart is how long they last. Symptoms of sinus infections tend to be less severe than allergies or respiratory infections, and they often last 10 days or more without getting better. 

Will a sinus infection go away on its own?

It depends. If your sinus infection is caused by a virus, it will go away on its own after about 7-10 days. But if your sinus infection is caused by a bacteria, you will need antibiotics from your doctor. 

What is the most accurate test for sinusitis?

Your doctor can do several sinus infection tests, but a CT scan can help your doctor see your full sinus cavity. It can also tell them where the swelling is located and if the sinus infection has spread. A CT scan can also find growths (polyps) in your nasal cavity that other tests missed.