Sinusitis can be diagnosed by case history and a thorough physical examination by the doctor. The physician will examine the nose to rule out any signs of nasal polyps or signs of inflammation.
Bacterial and viral sinusitis are difficult to distinguish. However, if symptoms last less than 10 days, it is generally due to a viral infection whereas symptoms lasting for more than 10 days are generally caused by a bacterial infection.
Viewing the sinuses through a fibre-optic scope (called nasal endoscopy or rhinoscopy) may help to diagnose sinusitis.
Imaging tests may be useful like-
- CT scan of the sinuses will help to diagnose sinusitis or to view the bones and tissues of the sinuses closely
- An MRI of the sinuses to rule out any tumor or fungal infections
For Sinusitis lasting more than 12 weeks, a CT scan is usually recommended. Nasal endoscopy may also be used to make a positive diagnosis.