What is Sinusitis
"Sinusitis" simply means your sinuses are inflamed―red and swollen―because of an infection or another problem. There are several types of sinusitis. Health experts usually identify them as follows:
- Acute, which lasts up to 4 weeks
- Subacute, which lasts 4 to 12 weeks
- Chronic, which lasts more than 12 weeks and can continue for months or even years
- Recurrent, with several attacks within a year
In 2009, the Centers for Disease Control and Prevention reported that nearly 31 million adults were diagnosed with sinusitis. Women were almost twice as likely as men to receive the diagnosis, and there were more cases in the southern United States than elsewhere in the country.
Where Are My Sinuses?
When people say, "My sinuses are killing me," they usually are referring to symptoms of congestion and achiness in one or more of the four pairs of cavities (air-filled spaces) known as paranasal sinuses. These small hollow spaces, which are located within the skull or bones of the head surrounding the nose, are named for the bones that contain them, as follows:
- Frontal sinuses over the eyes in the brow area
- Maxillary sinuses inside each cheekbone
- Ethmoid sinuses just behind the bridge of the nose, between the eyes
- Sphenoid sinuses behind the ethmoids in the upper region of the nose and behind the eyes
The paranasal sinuses open into the nasal cavity and are lined with cells that make mucus to keep the nose from drying out during breathing and to trap unwanted materials so that they do not reach the lungs.
What Are the Symptoms of Sinusitis?
- If you have pain in your forehead, the problem lies in your frontal sinuses.
- Pain in your upper jaw and teeth, with tender cheeks, may mean your maxillary sinuses are involved.
- Experiencing pain between your eyes, sometimes with swelling of the eyelids and tissues around your eyes, and tenderness when you touch the sides of your nose may mean sinusitis has developed in your ethmoid sinuses.
- Pain in your neck, with earaches, and deep achiness at the top of your head could be a sign that your sphenoid sinuses are involved (though these sinuses are affected less often).
Most people with sinusitis have pain or tenderness in several places, and their symptoms usually do not clearly indicate which sinuses are inflamed. Pain is not as common in chronic sinusitis as it is in acute sinusitis.
In addition to the pain, people who have sinusitis (acute or chronic) often have thick nasal secretions that can be white, yellowish, greenish, or blood-tinged. Sometimes these secretions drain in the back of the throat and are difficult to clear. This is referred to as “post-nasal drip.” Also, cases of acute and chronic sinusitis are usually accompanied by a stuffy nose, as well as by a general feeling of fullness over the entire face.
Less common symptoms of sinusitis (acute or chronic) can include the following:
- Tiredness
- Decreased sense of smell
- Cough that may be worse at night
- Sore throat
- Bad breath
- Fever
On very rare occasions, acute sinusitis can result in brain infection and other serious complications.
Because your nose can get stuffy or congested when you have a condition like the common cold, you may confuse simple nasal congestion with sinusitis. A cold usually lasts about 7 to 14 days and goes away without treatment. Acute sinusitis often lasts longer and typically causes more symptoms than a cold.
What Causes the Symptoms of Sinusitis?
The paranasal sinuses, like the inside of your nose, are lined with a thin layer of tissue called the mucous membrane, which produces mucus. This mucus flows out through openings of the paranasal sinuses and into the nose. When these openings become blocked, your sinuses are affected.
Anything that causes swelling in the nose can block the openings between your paranasal sinuses and your nose, including a cold, an allergic reaction such as hay fever, or a reaction to some chemical to which you've been exposed. The blockage causes air and mucus to become trapped within the sinuses. This may cause pain and thickened mucus.
- The pain of a sinus attack arises because the trapped air and mucus put pressure on the mucous membrane of the sinuses and the bony wall behind it. Also, when a swollen membrane at the opening of a paranasal sinus prevents air from entering into the sinuses, it can create a vacuum that causes pain.
- Mucus thickens because it loses its water content as it stays trapped inside the sinuses for a long time. In addition, inflammation leads to extra materials being secreted into the mucus, causing thickening.
What Are the Differences Between Acute and Chronic Sinusitis?
On this page:
- Acute Sinusitis
- Chronic Sinusitis
Acute Sinusitis
Acute sinusitis can be caused by the following:
- Common cold
- Allergies and other chronic conditions
- Pre-existing health conditions
Common cold
Most cases of acute sinusitis start with a common cold, which is caused by a virus. Colds can inflame your sinuses and cause symptoms of sinusitis. Both the cold and the sinus inflammation usually go away without treatment within two weeks. If the inflammation produced by the cold leads to infection caused by bacteria, then this infection becomes acute sinusitis.
The inflammation caused by the cold results in swelling of the mucous membranes of your sinuses, trapping air and mucus behind the narrowed sinus openings. When mucus stays inside your sinuses and is unable to drain into your nose, it can become the source of nutrients for bacteria, which can then multiply.
Most healthy people have bacteria, such as Streptococcus pneumoniae and Haemophilus influenzae, in their noses and throats. Usually, these bacteria cause no problems, but when you sniff or blow your nose when you have a cold, these actions create pressure changes that can send typically harmless bacteria into the sinuses. If your sinuses stop draining properly, the bacteria can begin to multiply in your sinuses, causing acute sinusitis.
Allergies and other chronic conditions
People who have allergies or other chronic problems that affect the nose also are prone to episodes of acute sinusitis. Chronic nasal problems cause the mucous membranes to swell and the sinus passages to become blocked. The normally harmless bacteria in your nose and throat again lead to acute sinusitis.
Pre-existing health conditions
In general, people who have reduced immune function, such as those with primary immune deficiency disease (a defect in the way the immune system responds to infection) or HIV infection, are more likely to suffer from sinusitis. People who have abnormal mucus secretion or mucus movement, such as those with cystic fibrosis (an inherited disease in which thick and sticky mucus clogs the lungs, causing breathing problems and making it easier for bacteria to grow), also are more likely to suffer from sinusitis.
Infections caused by fungi very rarely cause acute sinusitis because the human body has a natural resistance to fungi; however, in people whose immune systems are not functioning properly, fungi can cause acute sinusitis.
Chronic Sinusitis
In chronic sinusitis, the membranes of both the paranasal sinuses and the nose thicken because they are constantly inflamed. Most health experts now use the term “chronic rhinosinusitis” to describe this condition. They also recommend that the condition be distinguished as either rhinosinusitis with or rhinosinusitis without nasal polyps.
Nasal polyps are grape-like growths of the mucous membrane that protrude into the sinuses or nasal passages, making it even more difficult for the sinuses to drain and for air to pass through the nose. The causes of chronic rhinosinusitis are largely unknown, but there are some conditions that may put you at higher risk for developing it, including the following:
- Asthma and allergies
- Recurrent acute sinusitis
- Pre-existing health conditions
Asthma and allergies
Chronic rhinosinusitis often occurs in people who have asthma, many of whom also have allergies. It is possible that constant exposure to airborne allergens (substances that causes an allergic reaction) from house dust mites, pets, mold, and cockroaches causes chronic inflammation of the lining of the nose and the sinuses. An allergic reaction to certain fungi causes some cases of chronic rhinosinusitis: this condition is called allergic fungal sinusitis. However, at least half of all people who have chronic rhinosinusitis do not have allergies.
Recurrent acute sinusitis
Although most health experts believe that chronic rhinosinusitis is not an infectious disease like acute sinusitis, if you suffer from frequent episodes of acute sinusitis, you may be prone to developing chronic rhinosinusitis. Some experts believe that chronic rhinosinusitis is caused by an exaggerated immune response to fungi that normally are found in the sinuses or to the bacteriumStaphylococcus aureus, which commonly lives inside the nose.
Pre-existing health conditions
As with acute sinusitis, other causes of chronic rhinosinusitis may be an immune deficiency disorder or cystic fibrosis.
Some people are born with a physical structure inside the nose that makes mucus flow out of the sinuses difficult. Others may develop a structural problem after experiencing an injury to the nose. These people are at higher risk for developing chronic rhinosinusitis.
How Is Sinusitis Diagnosed?
Your healthcare professional usually can diagnose acute sinusitis by noting your symptoms and examining your nose and face. If your symptoms do not clearly indicate that you have sinusitis or if they persist for a long time and do not get better with treatment, your healthcare professional may order a CT (computerized tomography) scan (a form of X-ray that shows some soft-tissue and other structures that cannot be seen in conventional X-rays) to confirm that you have sinusitis.
Other laboratory tests your healthcare professional may use to check for possible causes of chronic rhinosinusitis include the following:
- Blood tests to rule out conditions, such as an immune deficiency disorder, that are associated with sinusitis
- A sweat test or a blood test to rule out cystic fibrosis
- Tests on the material inside your sinuses to detect bacterial or fungal infection
How Is Sinusitis Treated?
After diagnosing sinusitis and identifying a possible cause, your healthcare professional can suggest various treatments.
Acute sinusitis
If you have acute sinusitis, your healthcare professional may recommend the following:
- Antibiotics to control a bacterial infection, if present
- Pain relievers to reduce any pain
- Decongestants (medicines that shrink the swollen membranes in the nose and make it easier to breathe)
Even if you have acute sinusitis, your healthcare professional may choose not to use an antibiotic because many cases of acute sinusitis will end on their own. However, if you do not feel better after a few days, you should contact your healthcare professional again.
Follow your healthcare professional's instruction on how to use over-the-counter or prescription decongestant nose drops and sprays. You should use these medicines for only a few days, as longer term use can lead to even more congestion and swelling of your nasal passages.
If you suffer from nasal allergies, such as hay fever, along with sinusitis, your healthcare professional may recommend medicine to control your allergies. This may include a nasal steroid spray that reduces the swelling around the sinus passages and allows the sinuses to drain.
If you have asthma and then get sinusitis, your asthma may worsen. You should contact your healthcare professional, who may change your asthma treatment.
Chronic rhinosinusitis
Healthcare professionals often find it difficult to treat chronic rhinosinusitis successfully. They have two options to offer patients: medicine and surgery.
Medicine
- Nasal steroid sprays are helpful for many people, but most people still do not get full relief of symptoms with these medicines.
- A long course of antibiotics is occasionally recommended by physicians, but results from clinical research do not support this kind of antibiotic use.
- Saline (saltwater) washes or saline nasal sprays can be helpful in chronic rhinosinusitis because they remove thick secretions and allow the sinuses to drain.
- Oral steroids, such as prednisone, may be prescribed for severe chronic rhinosinusitis. However, oral steroids are powerful medicines with significant side effects, and these medicines typically are prescribed when other medicines have failed.
Research is needed to develop new, more effective treatments.
Surgery
When medicine fails, surgery may be the only alternative for treating chronic rhinosinusitis. The goal of surgery is to improve sinus drainage and reduce blockage of the nasal passages. Nasal surgery usually is performed to accomplish the following:
- Enlarge the natural openings of the sinuses
- Remove nasal polyps
- Correct significant structural problems inside the nose and the sinuses if they contribute to sinus obstruction
Although most people have fewer symptoms and a better quality of life after surgery, problems can reoccur, sometimes even after a short period of time.
In children, problems can sometimes be eliminated by removing the adenoids. These gland-like tissues, located high in the throat behind and above the roof of the mouth, can obstruct the nasal passages.
Can Sinusitis Be Prevented?
There are no methods that have been scientifically proven to prevent acute or chronic sinusitis. Your healthcare professional may recommend the following measures that can help:
- Keep your nose as moist as possible with frequent use of saline sprays or washes.
- Avoid very dry indoor environments and use a humidifier, if necessary. Be aware, however, that a humid environment also may increase the amount of mold, dust mite, or cockroach allergens in your home; this is important only if you are allergic to any of those organisms.
- Avoid exposure to irritants such as cigarette and cigar smoke or strong odors from chemicals.
- Avoid exposure to substances to which you are allergic.
- If you haven’t been tested for allergies and you are getting frequent sinus infections, ask your healthcare professional to give you an allergy evaluation or refer you to an allergy specialist.
- Avoid long periods of swimming in pools treated with chlorine, which can irritate the lining of the nose and sinuses.
- Avoid water diving, which forces water into the sinuses from the nasal passages.
Are Researchers Studying Sinusitis?
NIAID supports research to better understand the immune system in health and disease and to develop new treatments. Examples of NIAID-supported research to improve our understanding of the causes of sinusitis and to develop treatments for the condition include the following:
- Most people who have moderate to severe asthma also have chronic rhinosinusitis, suggesting that these two diseases may be the same disease occurring in the lower and upper parts of the respiratory system, respectively. NIAID supports research to understand the causes of chronic airway inflammation in asthma that could help scientists understand chronic rhinosinusitis and develop more effective treatment and prevention strategies.
- At least two-thirds of acute sinusitis cases are caused by two bacteria: Streptococcus pneumoniae and Haemophilus influenzae. NIAID supports studies to better understand how these bacteria cause infection and to identify potential targets for future vaccination strategies that could prevent these infections.
- NIAID funds research that examines the causes of thickening and inflammation of the lining of the sinuses and nasal passages. These projects also focus on the cells that produce mucus and line the sinuses and nasal passages.
- In many people who have chronic rhinosinusitis, especially those with nasal polyps, a large number of eosinophils (white blood cells that have strong inflammatory properties) are found in the tissues that line the sinuses and nasal passages. NIAID funds several projects that examine the role of eosinophils and the messenger molecules they produce in causing chronic sinus inflammation and chronic rhinosinusitis with polyps.
- NIAID supports research to test the theory that chronic rhinosinusitis is caused by an exaggerated immune response to fungi. One study has shown that when blood cells from people who have chronic rhinosinusitis are exposed to fungal material, these cells make messenger molecules that cause inflammation.
- NIAID supports projects to identify human genes and proteins that are different in patients who have chronic rhinosinusitis from those whose sinuses are healthy. The results will help us understand the causes of chronic rhinosinusitis and develop promising new treatments. For example, research has found that some people who have chronic rhinosinusitis also have certain alterations in the gene that causes cystic fibrosis.
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