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Diagnosis of Sinusitis

The doctor will ask about symptoms and past health. A physical exam will be done. The symptoms and exam may be enough to make the diagnosis.

If acute sinusitis is suspected, no tests may be done.

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

  • 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 nasal discharge, or discharge with pus—lasts 3 to 4 days or more

Tests that may be done in certain situations include:

Transillumination

This procedure involves shining a bright light over the cheek. This is done in a dark room. If light does not show through certain areas of the face, there may be a sinus infection. This test is not very reliable and is not used very often.

Nasal Endoscopy

This procedure uses a slim, flexible tube. The tube has a light at the end (endoscope). It is inserted into the nose. The doctor can inspect the nose and the openings of the sinuses. Tissue samples or biopsies may be taken, if needed. The samples can then be sent to the lab. The lab will look for fungus, a tumor, or other uncommon causes of sinusitis.

Nasal Culture

The doctor will take a sample of nasal discharge. It is sent to the lab and checked for bacteria. The culture may be obtained during nasal endoscopy. Nasal cultures are usually not done for healthy people with acute sinusitis.

Sinus X-ray

X-rays of the sinuses may sometimes be taken. They may help confirm a diagnosis of acute sinusitis.

CT scan

CT scans are imaging tests. They can help see areas that sinus x-rays may not see. CT scans are most effective for diagnosing chronic sinusitis.

MRI scan

An MRI scan may be done to look for problems related to sinusitis.

Sweat Chloride Test

This is a test for cystic fibrosis. It may be given to children who also have polyps and/or chronic sinus infections.

Blood Tests for Immune Function

The doctor may request these tests for recurrent or chronic sinusitis.

Sinus Puncture

This test may be done if the diagnosis is uncertain. The test uses a needle to remove a bit of fluid from the sinuses. This fluid is then sent to a lab to identify the bacteria.

REFERENCES:

Acute rhinosinusitis in adults. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/acute-rhinosinusitis-in-adults. Accessed November 15, 2021.

Chronic rhinosinusitis. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/chronic-rhinosinusitis. Accessed November 15, 2021.

Shay AD, Tajudeen BA. Histopathologic analysis in the diagnosis and management of chronic rhinosinusitis. Curr Opin Otolaryngol Head Neck Surg. 2019;27(1):20-24.

Sinusitis. American Academy of Otolaryngology—Head and Neck Surgery website. Available at: https://www.enthealth.org/conditions/sinusitis/. Accessed November 15, 2021.

Sinusitis overview. American Academy of Allergy, Asthma & Immunology website. Available at: https://www.aaaai.org/Conditions-Treatments/allergies/sinusitis. Accessed November 15, 2021.

Last reviewed November 2021 by EBSCO Medical Review Board David L. Horn, MD, FACP  Last Updated: 11/17/2021