Diagnosis

Physical Examination

The doctor will press the forehead and cheekbones to check for tenderness and check for other signs of sinusitis, including yellow to yellow-green nasal discharge. The doctor will also check the inside of the nasal passages using a device with a bright light to check the mucus and look for any structural abnormalities.

Laboratory Tests

In some cases, tests may be used to detect that presence of immune factors in sinus tissues that would suggest persistent inflammation. Such findings would strongly suggest a chronic or allergic condition. In 2005, a new laboratory test became available for diagnosing chronic sinusitis. The CRS Fungal Profile tests mucus samples for eosinophil major basic protein (a protein involved in allergic and inflammatory reactions) and a type of fungi.

Nasal Endoscopy (Rhinoscopy)

Nasal endoscopy, or rhinoscopy, is now used for diagnosing chronic and recurrent acute sinusitis and for differentiating between allergies and true acute sinusitis. It involves the insertion of a flexible tube into the nasal passage and the use of a fiberoptic light that enables the doctor to see inside the sinuses. Endoscopy allows detection of even very small abnormalities in the sinuses. It can determine whether surgery is necessary and if medications are having any effect. Bacterial cultures can also be taken from samples removed using endoscopy. (Endoscopy is also used for treating sinusitis.)

Imaging Techniques

Computer Tomography. Computed tomography (CT) scanning is the best method for viewing the paranasal sinuses. There is little relationship, however, between symptoms in most patients and findings of abnormalities on a CT scan. CT scans are recommended for acute sinusitis only if there is a severe infection, complications, or a high risk for complications. CT scans are useful for diagnosing chronic or recurrent acute sinusitis and for surgeons as a guide during surgery. They show inflammation and swelling and the extent of the infection, including that in deep hidden air chambers missed by x-rays and nasal endoscopy. Often, they can detect the presence of fungal infections.

X-Rays. Until the availability of endoscopy and CT scans, x-rays were commonly used. They are not as accurate, however as these procedure in identifying abnormalities in the sinuses. For example, more than one x-ray is needed for diagnosing frontal and sphenoid sinusitis. X-rays do not detect ethmoid sinusitis at all, which can be the primary site of an infection that has spread to the maxillary or frontal sinuses.