Diagnosis of Sinusitis

Diagnosis of Sinusitis

Your doctor will ask about your symptoms. A physical examination will be done. The doctor will often be able to make a diagnosis based on your symptoms and the physical exam.

Infectious Disease Society of America (IDSA) base the diagnosis of acute sinusitis on the presence of certain symptoms. Acute sinusitis will have at least 2 of the following major symptoms or 1 major symptom plus 2 or more minor symptoms:

  • Major symptoms include:
    • Nasal congestion or obstruction
    • Facial congestion or fullness
    • Facial pain or pressure
    • Discharge with pus from nose
    • Rear nasal discharge that has pus or is discolored
    • Decreased or no ability to smell
    • Fever
  • Minor symptoms include:
    • Headache
    • Ear pain, pressure, or fullness
    • Bad breath
    • Dental pain
    • Cough
    • Fatigue

Your doctor may need to decide if a virus or bacteria caused the sinusitis. Infections caused by bacteria may have the following characteristics:

  • Signs or symptoms lasting 10 days or more without any signs of improvement
  • Worsening signs or symptoms after a period of improvement
  • Severe symptoms such as fever 102 °F (degrees Fahrenheit); 39 ºC (degrees Celsius) or more and nasal discharge with pus that lasts 3 to 4 consecutive days or more

Other tests that may be done in certain situation include:


This simple procedure involves shining a bright light (as from a flashlight) over your cheek in a dark room. If no light illuminates certain areas of your face, then it’s likely that you have a sinus infection. This test is not very reliable and is not commonly performed.

Nasal Culture

Your doctor might send a sample of your nasal discharge to a laboratory, where it can be tested for the presence of bacteria. Accurate evaluation of a nasal culture usually requires that the culture be obtained during nasal endoscopy. If you are healthy and have acute sinusitis, a nasal culture is usually not done.

Sinus X-ray

X-rays of the sinuses are of limited use for diagnosing the presence of acute sinusitis.

CT scan

This type of imaging study can be useful for diagnosing sinusitis, including in those areas not well visualized by sinus x-rays. CT scans are particularly effective for diagnosing chronic sinusitis.

MRI scan

Your doctor may order an MRI scan if complications of sinusitis are suspected.

Sweat Chloride Test

This is a test for cystic fibrosis in children who also have polyps and/or chronic sinus infections.

Blood Tests for Immune Function

Your doctor may request these tests if you have recurrent or chronic sinusitis.

Sinus Puncture

If there’s some confusion about your diagnosis, your doctor may choose to send you to a specialist to have a sinus puncture performed. This involves using a needle to remove a bit of fluid from within your sinuses. This fluid will then be sent to a lab to identify the infecting bacteria and to determine the most effective type of antibiotic for treatment.

Nasal Endoscopy

This procedure uses a slim, flexible tube with a fiberoptic light at the end (endoscope). It is inserted into your nose. Your doctor can inspect the mucosa of the nose and the openings of the sinuses. If indicated, he can also take samples or biopsies through the endoscope for lab examination to look for fungus, tumor, or other uncommon causes of your sinusitis.



Acute sinusitis in adults. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/acute-rhinosinusitis-in-adults. Updated September 12, 2016. Accessed August 15, 2017.
Alho OP. Viral infections and susceptibility to recurrent sinusitis. Curr Allergy Asthma Rep. 2005;5(6):477-481
Chronic rhinosinusitis. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/chronic-rhinosinusitis. Updated August 7, 2016. Accessed August 15, 2017.
Sinusitis. American Academy of Otolaryngology—Head and Neck Surgery website. Available at:
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Accessed August 15, 2017.
Sinusitis overview. American Academy of Allergy, Asthma & Immunology website. Available at:
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Accessed August 15, 2017.
Last reviewed September 2018 by David L. Horn, MD, FACP
Last Updated: 12/1/2020

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