Sinusitis (sy-nyoo-SY-tis) is an inflammation of the sinuses (SY-nuh-ses), the hollow chambers or cavities located in the bones of the face that surround the nose.
Sinusitis refers to swelling of the tissue lining the sinuses. Normally, the sinuses are filled with air; but when sinuses become blocked and filled with fluid, germs (bacteria, viruses, and fungi) can grow and cause an infection.
Causes of sinus blockage include the common cold; certain allergies; nasal polyps (small growths in the lining of the nose); or a deviated septum (a displacement of the bony structure that divides the nasal cavity).
People have four pairs of paranasal sinuses (the sinuses surrounding the nose):
The sinuses and the narrow tubelike structures that link them to the nasal passages are lined with the same mucous membranes * that line the nose. Colds, allergies * , and exposure to some chemicals can cause swelling and inflammation in the lining of the sinus passages and block sinus drainage. Bacteria (such as Streptococcus pneumoniae, STREP-tuh-KAH-kus nu-MO-nye), viruses, and fungi * that live in the body may become trapped, multiply, and invade the inflamed sinuses.
People with allergies, asthma * , and cystic fibrosis* are more likely to have sinus infections. Other candidates for sinusitis are people with a weakened immune system, such as those who have AIDS * or cancer; people with narrow sinus passages or with growths or blockages in the nasal area, such as tumors * or polyps * ; and people with previously broken or deformed nasal bones. The risk of sinusitis also is higher when people swim or dive, due to the pressure these activities put on the sinus cavities.
Physicians classify sinusitis in three ways:
The Centers for Disease Control and Prevention (CDC) estimates that 29.4 million adults have diagnosed sinusitis as of 2014. This figure means that 12.3 percent of all people over the age 18 in the United States are afflicted with this disorder. It is a health problem that causes 11.7 million visits to American doctors’ offices each year.
No one can catch a sinus infection from another person, but the viruses and bacteria that cause colds and other respiratory tract * infections that can trigger sinusitis may spread from person to person in droplets of fluid from the nose or mouth. When people who have sinusitis cough, sneeze, laugh, or talk, they can transmit germs to their hands, to the surfaces around them, and into the air. Others can then breathe in the germs or touch contaminated surfaces with their hands and spread the germs to their noses and mouths. Such infections sometimes develop into sinusitis.
Symptoms of a cold (runny nose and low fever) often give way to pain and pressure in the sinuses, which are usually the first signs of sinusitis. Other symptoms of sinusitis include:
People with sinusitis occasionally develop earaches, neck pain, or a sore throat caused by mucus * draining from the sinuses into the throat.
Some other conditions have symptoms similar to the symptoms of sinusitis, but they are not the same as sinusitis. Many people confuse nasal congestion (stuffy nose) with sinusitis. In addition, considerable confusion exists about what people call “sinus headaches”; some studies have indicated that up to 90 percent of these headaches are actually not related to the sinuses.
To diagnose sinusitis, doctors look for the signs and symptoms of the condition in the patient. They suspect sinusitis if a patient has cold symptoms that last for more than 10 days, or if the patient has other sinusitis symptoms. A doctor may, for example, tap the patient's face to determine whether the sinuses are tender. If a patient has complicated or repeated cases of sinusitis, a doctor may order x-rays or a computed tomography * (CT) scan to determine whether the sinuses are inflamed.
Beyond these treatments, individuals can try to relieve the symptoms of sinusitis in several ways. They can take acetaminophen * to help ease the pain and use nonprescription decongestants, taken by mouth or in the nose through sprays, to lessen stuffiness. However, using a decongestant nasal spray for more than a few days may itself cause rebound congestion or swelling of the sinuses and slow recovery. Saline or salt sprays may also reduce swelling in the sinuses. Some patients find relief by placing a warm compress over the infected sinuses; using a steam vaporizer * ; or sitting in a warm, steamy bathroom. Doctors may prescribe special nasal sprays or oral (by mouth) medications for people with chronic sinusitis who have allergies that contribute to the infection. Chronic sinusitis sufferers often benefit from sinus irrigation or flushing, and many different devices are available for this purpose. For chronic or recurrent sinusitis, doctors may refer the patient to an ear, nose, and throat specialist.
In some cases, people with severe chronic sinusitis may undergo surgery to enlarge their sinus passages, remove a polyp, or fix a deviated septum * that might be blocking sinus drainage.
Complications of sinusitis are rare, but they do occur. Sinusitis can cause osteomyelitis * when the infection from the sinus spreads into the bones of the face or skull. Sinusitis can also lead to an infection of brain tissue or meningitis (inflammation of the meninges * ). In addition, a sinus infection can spread to invade the tissues surrounding the eyes.
Because no practical way exists to prevent all colds or to eliminate all allergies, sinusitis is not entirely preventable. People can limit their exposure to the viruses and bacteria that cause the infections by washing their hands thoroughly and frequently, and by not sharing eating or drinking utensils. Individuals should also avoid smoking as well as exposure to tobacco smoke to help limit the risk of sinusitis. People with allergies should avoid whatever triggers their allergy symptoms, and control their allergies with the treatment recommended by their doctors. Drinking plenty of fluids and keeping the air in the house moist by using a vaporizer can help thin mucus and prevent its buildup in the sinuses. Limiting alcohol consumption also may help because alcohol can cause nasal membranes to swell. In addition, air travel and underwater diving can cause significant discomfort in individuals with acute or chronic sinusitis, so they may wish to consider using decongestants prior to these activities.
See also Allergies • Antibiotic Resistance • Bacterial Infections • Common Cold • Fever • Headache • Infection • Influenza • Osteomyelitis • Streptococcal Infections • Viral Infections
Earlstein, Frederick. Sinusitis, Hay Fever, Allergic Rhinitis Explained. Manassas, VA: NRB Publishing. 2014.
Centers for Disease Control and Preventions (CDC). “Chronic Sinusitis.” http://www.cdc.gov/nchs/fastats/sinuses.htm (accessed July 10, 2016).
MedlinePlus. “Sinusitis.” U.S. National Library of Medicine, National Institutes of Health. https://www.nlm.nih.gov/medlineplus/sinusitis.html (accessed July 10, 2016).
U.S. Food and Drug Administration (FDA). “Is Rinsing Your Sinuses Safe?” http://www.fda.gov/ForConsumers/ConsumerUpdates/ucm316375.htm (accessed July 10, 2016).
American Academy of Otolaryngology—Head and Neck Surgery. 1650 Diagonal Rd., Alexandria, VA 22314-2857. Telephone: 703-836-4444. http://www.entnet.org (accessed July 10, 2016).
American Rhinologic Society. PO Box 495, Warwick, NY 10990-0495. Telephone: 845-988-1631. Website: http://www.american-rhinologic.org (accessed July 10, 2016).
Centers for Disease Control and Prevention. 1600 Clifton Rd. Atlanta, GA 30329-4027. Toll-free: 800-232-4636. Website: http://www.cdc.gov (accessed July 10, 2016).
National Institute of Allergy and Infectious Diseases. Office of Communications and Government Relations, 5601 Fishers Ln., MSC 9806, Bethesda, MD 20892-9806 Telephone: 301-496-5717. Website: www.niaid.nih.gov (accessed July 10, 2016).
* mucous membranes are the thin layers of tissue found inside the nose, ears, cervix (SER-viks) and uterus, stomach, colon and rectum, on the vocal cords, and in other parts of the body.
* allergies (AL-uhr-jeez) are immune system–related sensitivities to certain substances, such as cat dander or the pollen of certain plants, which cause sneezing, runny nose, wheezing, or swollen, itchy patches on the skin called hives.
* fungi (FUNG-eye) are microorganisms that can grow in or on the body, causing infections of internal organs or of the skin, hair, and nails.
* asthma (AZ-mah) is a condition in which the airways of the lungs repeatedly become narrowed and inflamed, causing difficult breathing.
* cystic fibrosis (SIS-tik fy-BRO-sis) is a disease that causes the body to produce thick mucus that clogs passages in many of the body's organs, including the lungs.
* AIDS, or acquired immunodeficiency (ih-myoo-no-dih-FIH-shensee) syndrome, is an infection that severely weakens the immune system. It is caused by the human immunodeficiency virus (HIV).
* tumors (TOO-morz) are abnormal growths of body tissue that have no known cause or physiologic purpose. Tumors may or may not be cancerous.
* polyps (PAH-lips) are bumps or growths, usually on the lining or surface of a body part (such as the nose or intestine). Their size can range from tiny to large enough to cause pain or obstruction.
* respiratory tract includes the nose, mouth, throat, and lungs. It is the pathway through which air and gases are transported down into the lungs and returned from the body.
* mucus (MYOO-kus) is a thick slippery substance that lines the interior of many body parts.
* computed tomography (kom-PYOO-ted toe-MAH-gruh-fee), or CT, formerly called computerized axial tomography (CAT), is a technique in which a machine takes many x-rays of the body to create a three-dimensional picture.
* antibiotic resistance occurs when bacteria evolve to withstand attack by antibiotics.
* acetaminophen (uh-see-tehMIH-noh-fen) is a medication commonly used to reduce fever and relieve pain.
* vaporizer is a device that converts water (or a liquid medication) into a vapor, a suspension of tiny droplets that remain in the air and can be inhaled.
* deviated septum is a condition in which the wall of tissue between the nasal passages, the septum, divides the passageways unevenly, sometimes causing breathing difficulties and blocking drainage from the sinuses.
* osteomyelitis (ah-stee-o-my-uhLYE-tis) is a bone infection that is usually caused by bacteria. It can involve any bone in the body, but it most commonly affects the long bones in the arms and legs.
* meninges (meh-NIN-jeez) are the membranes that cover and protect the brain and the spinal cord.