Sinusitis is inflammation of the sinuses, most commonly caused by a viral or bacterial infection or by an allergy.

• Some of the most common symptoms of sinusitis are pain, tenderness, nasal congestion, and headache.
• The diagnosis is based on symptoms, but sometimes x-rays or other imaging tests are needed.
• Antibiotics can eliminate the underlying infection.

Sinusitis is one of the most common medical conditions. About 10 to 15 million people each year develop symptoms of sinusitis. Sinusitis may occur in any of the four groups of sinuses: maxillary, ethmoid, frontal, or sphenoid. Sinusitis nearly always occurs in conjunction with inflammation of the nasal passages (rhinitis), and some doctors refer to the disorder as rhinosinusitis. It may be acute (short-lived) or chronic (long-standing).

Acute Sinusitis: Sinusitis is defined as acute if it is totally resolved in less than 30 days. Acute sinusitis may be caused by a variety of bacteria and often develops after something blocks the openings to the sinuses. Such blockage commonly results from a viral infection of the upper airways, such as the common cold. During a cold, the swollen mucous membranes of the nasal cavity tend to block the openings of the sinuses. Air in the sinuses is absorbed into the bloodstream, and the pressure inside the sinuses decreases, causing pain and drawing fluid into the sinuses. This fluid is a breeding ground for bacteria. White blood cells and more fluid enter the sinuses to fight the bacteria. This influx increases the pressure and causes more pain.

Allergies also cause mucous membrane swelling, which blocks the openings to the sinuses. Additionally, people with a deviated septum are more prone to obstructed sinuses.

Locating the Sinuses The sinuses are hollow cavities in the bones around the nose. The two frontal sinuses are located just above the eyebrows. The two maxillary sinuses are located in the cheekbones, and the two groups of ethmoid sinuses are located on either side of the nasal cavity. The two sphenoid sinuses (not shown) are located behind the ethmoid sinuses.

Chronic Sinusitis: Sinusitis is defined as chronic if it has been ongoing for more than 8 to 12 weeks. Doctors do not understand exactly what causes chronic sinusitis, but it may follow a viral infection, a severe allergy, or exposure to an environmental pollutant. Often the person has a family history, and a genetic predisposition seems to be a factor. If the person has a bacterial or fungal infection, the inflammation is much worse. Occasionally, chronic sinusitis of the maxillary sinus results when an upper tooth abscess spreads into the sinus above.

Symptoms

Acute sinusitis usually results in pain, tenderness, congestion and obstruction in the nose, reduced ability to smell (hyposmia), bad breath (halitosis), a productive cough (especially at night), and swelling over the affected sinus. Maxillary sinusitis causes pain over the cheeks just below the eyes, toothache, and headache. Frontal sinusitis causes headache over the forehead. Ethmoid sinusitis causes pain behind and between the eyes, a bacterial infection of the skin around the eye socket (periorbital cellulitis), tearing, and headache (often described as splitting) over the forehead. Sphenoid sinusitis causes pain that does not occur in well-defined areas and may be felt in the front or back of the head.

In acute sinusitis, yellow or green pus may be discharged from the nose. Fever and chills also can occur, but their presence may suggest that the infection has spread beyond the sinuses. Any change in vision or swelling around the eye is a very serious condition that can quickly—within minutes to hours—result in blindness. Such a change should be evaluated by a doctor as soon as possible. Often, pain is more severe in acute sinusitis.

The symptoms of chronic sinusitis are similar to those caused by acute sinusitis. The most common symptoms of chronic sinusitis are nasal obstruction, nasal congestion, and postnasal drip. People with sinusitis may have colored discharge and a decreased sense of smell. A person also may feel generally ill (malaise).

Diagnosis

A doctor bases the diagnosis on the typical symptoms and, sometimes, on x-ray studies. X-rays may show fluid in the sinuses, but a computed tomography (CT) scan is better able to determine the extent and severity of sinusitis. If a person has maxillary sinusitis, the teeth may be x-rayed to check for tooth abscesses. Sometimes a doctor passes a thin viewing scope (endoscope) into the nose to inspect the sinus openings and to obtain samples of fluid for culture. This procedure, which requires a local anesthetic (to numb the area), can be done in the doctor's office.

Sinusitis in children is suspected when a pus-filled discharge from the nose persists for more than 10 days along with extreme tiredness (fatigue) and cough. Pain or discomfort in the face may be present. Fever is uncommon. When examining the nose, a doctor sees pus-filled drainage. A CT scan can confirm the diagnosis.

Treatment

Treatment of acute sinusitis is aimed at improving sinus drainage and curing the infection. Steam inhalation; hot, wet towels over the affected sinuses; and hot beverages may help relieve the tightened or constricted blood vessels and promote drainage. Nasal sprays, such as phenylephrine, which cause blood vessels to narrow (constrict), can be used for a limited time. Similar drugs, such as pseudoephedrine, taken by mouth are not as effective. For acute sinusitis, antibiotics such as amoxicillin or trimethoprim/sulfamethoxazole are given.

People who have chronic sinusitis take antibiotics, such as amoxicillin/clavulanate or cefuroxime, for a longer period of time. When antibiotics are not effective, surgery may be performed either to wash out the sinus and obtain material for culture or to improve sinus drainage, which allows the inflammation to resolve.

Fungal Sinus Infections
A variety of fungi that are normally found throughout the environment can be present in the nose and sinuses of most healthy people. In certain situations, however, fungi can cause significant nasal and sinus inflammation. Fungus balls are overgrowths of fungi in otherwise healthy people. Symptoms include sinus pain, pressure, nasal congestion, drainage of fluids, and chronic infections. Surgery is needed to open the affected sinus and remove the fungal debris. Allergic fungal sinusitis is a disorder in which fungi cause a reaction characterized by marked nasal congestion and the formation of nasal and sinus polyps. The polyps obstruct the nose and the openings to the sinuses and cause chronic inflammation. The polyps and inflammation often involve only one side of the nose. Surgery is typically required to open up the sinuses and to remove the fungal debris. Long-term treatment is also required with corticosteroids, antibiotics, and, sometimes, antifungal drugs applied directly to the area or taken by mouth. These drugs reduce the inflammation and eliminate the fungus. However, even after prolonged treatment, the disorder is very likely to recur. Invasive fungal sinusitis is a very serious disorder that develops most often in people whose immune system is impaired by chemotherapy or by diseases such as poorly controlled diabetes, leukemia, lymphoma, multiple myeloma, or AIDS. It may spread rapidly. Symptoms include pain, fever, and discharge of pus from the nose. The fungus may spread to the eye socket, causing a bulging of the affected eye (proptosis) and blindness. A doctor bases the diagnosis on the results of a biopsy (removal of a tissue sample for identification under a microscope). Treatment is with surgery and antifungal drugs given by vein. Doctors also must control the underlying disease and stimulate a weakened immune system because these infections can cause death.

Last full review/revision July 2008 by Marvin P. Fried, MD; Michael Jacewicz, MD