Diagnosis:

Patients should see a doctor if they have sinusitis symptoms that do not clear up within a few days, are severe, or are accompanied by high fever or acute illness. However, only one-half to two-thirds of patients with such symptoms actually have sinusitis.

Some doctors believe that too many patients are diagnosed with true sinusitis and given unnecessary antibiotics when their symptoms would actually resolve easily in days with over-the-counter medications or no drugs at all.

The first goal in diagnosing sinusitis is to rule out other possible causes of symptoms, and then determine:

• The site where the infection has occurred
• Whether the condition is acute or chronic
• The organism causing the infection (if possible)

Diagnostic Approach to Acute Sinusitis

Medical History. The patient should describe all symptoms such as nasal discharge and specific pain in the face and head, including eye and tooth pain.

After assessing symptoms, the doctor should take a thorough medical history of the patient:

• Any history of allergies or headaches
• Recent upper respiratory infection (colds, flus, infection) and how long they have lasted
• History of sinusitis episodes that is unresponsive to antibiotic treatment. (In such cases, the doctor will usually diagnose chronic or recurrent acute sinusitis and may refer the patient to a specialist for more advanced testing.)
• Exposure to cigarette smoke or other environmental pollutants
• Recent travel
• Recent dental procedures
• Medications being taken (particularly decongestants)
• Any known structural abnormalities in the nose and face
• Injury to the head or face
• History of medical conditions, such as chronic fatigue syndrome or fibromyalgia, which can produce tender areas in the face or sinus regions and nonspecific symptoms of ill health
• Any family history of allergies, immune disorders, cystic fibrosis, or immotile cilia syndrome
• In small children with sinusitis, whether they attend a day care center or nursery school

Physical Examination

The doctor will press the forehead and cheekbones to check for tenderness and 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.

Nasal Endoscopy (Rhinoscopy)

Nasal endoscopy, or rhinoscopy, involves the insertion of a flexible tube with a fiberoptic light on the end into the nasal passage. Rhinoscopy allows detection of even very small abnormalities in the nasal passages and can better evaluate structural problems of the nasal septum, as well as the presence of soft tissue masses such as polyps. It may also identify small amounts of pus draining from the opening of a sinus. 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 in deeply 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, 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. This area can be the primary site of an infection that has spread to the maxillary or frontal sinuses.

Magnetic Resonance Imaging. Magnetic resonance imaging (MRI) is not as effective as CT in defining the paranasal anatomy and therefore is not typically used to image the sinuses for suspected sinusitis. MRI is also more expensive than CT. However, it can help rule out fungal sinusitis and may help differentiate between inflammatory disease, malignant tumors, and complications within the skull. It may also be useful for showing soft tissue involvement.

Sinus Puncture and Bacterial Culture

Sinus puncture with bacterial culture is the gold standard for diagnosing a bacterial sinus infection. It is invasive, however, and is performed only when antibiotics have not worked. Sinus puncture involves using a needle to withdraw a small amount of fluid from the sinuses. It requires a local anesthetic and is performed by a specialist. The fluid is then cultured to determine what type of bacteria is causing sinusitis.