What is it?
Nasal polyps are teardrop-shaped, noncancerous growths on the lining of your nasal passages or sinuses.
Small nasal polyps may cause no problems and go unnoticed. Larger nasal polyps can block your nasal passages or sinuses and cause breathing difficulties, a loss of your sense of smell, frequent sinus infections and other problems.
Although nasal polyps can affect anyone, they're more common in adults, particularly those with asthma, frequent sinus infections and allergies. Children with cystic fibrosis often develop nasal polyps.
Medications can often lessen the size of nasal polyps or eliminate them, but surgery is sometimes necessary to remove them. Even after successful treatments, nasal polyps often return.
Nasal polyps are associated with chronic inflammation of the lining of your nasal passages and sinuses (chronic sinusitis). If you have several polyps or large polyps, they may obstruct your nasal passages and sinuses. As a result of these conditions in your nose and sinuses, you may experience some of the following signs and symptoms:
- A runny nose
- Persistent stuffiness
- Postnasal drip
- Decreased or no sense of smell
- Loss of sense of taste
- Facial pain or headache
- Itching around your eyes
You may have small nasal polyps and experience no signs or symptoms.
Your nasal passages and sinuses are lined with mucous membrane, tissue that secretes sticky fluids (mucous). The membrane contains many tiny blood vessels and is covered in tiny hair-like structures called cilia.
When you inhale, the nasal passages and sinuses provide a sort of entryway with lots of "nooks and crannies" where air can be warmed and moistened before traveling to your lungs. The air is also cleaned. Tiny particles in the air stick to the mucous, and the cilia sweep them to the front of your nose or to the back of your throat.
Development of nasal polyps
Nasal polyps can form when the mucous membrane of your nasal passages and sinuses is chronically inflamed. A nasal or sinus condition is generally defined as chronic if the signs and symptoms of inflammation last more than 12 weeks.
It's unclear exactly how chronic inflammation leads to the formation of polyps, but the response of your immune system in the mucous membrane appears to contribute.
Nasal polyps may develop anywhere throughout the nasal passages or sinuses, but they appear most often near the openings to your sinuses.
Any condition that contributes to chronic inflammation in your nasal passages or sinuses (chronic sinusitis), such as infections or allergies, may increase your risk of nasal polyps. Conditions often associated with nasal polyps include:
- Asthma, a disease that causes inflammation and constriction of airways
- Aspirin sensitivity, an allergy-like response to aspirin or other nonsteroidal anti-inflammatory drugs — such as ibuprofen and naproxen
- Allergic fungal sinusitis, an allergy to airborne fungi
- Cystic fibrosis, a genetic disorder that results in the production and secretion of abnormal fluids, including thick mucus from nasal and sinus membranes
- Churg-Strauss syndrome, a rare disease that causes the inflammation of blood vessels
Other risk factors include:
- Age. Nasal polyps are more common in adults.
- Family history. There is some evidence that you may inherit a gene or genes that make you more likely to develop nasal polyps.
The presence of several polyps (polyposis) or a single large polyp may block the normal flow of air or the draining of fluids out of your sinuses or nasal cavity. Resulting complications may include:
- Frequent or chronic sinus infections
- Obstructive sleep apnea, a potentially serious condition in which you stop and start breathing a number of times during sleep
- Altered facial structure leading to double vision or unusually wide-set eyes (more likely associated with cystic fibrosis)
Polyps may be visible with the aid of a simple lighted instrument.
Other diagnostic tests include:
- Nasal endoscopy. A nasal endoscope, a narrow tube with a magnifying lens or tiny camera, enables your doctor to look at the inside of your nose in detail. He or she inserts the endoscope into a nostril and guides it into your nasal cavity to locate nasal polyps.
- Computerized tomography (CT) scan. Computerized tomography is a type of X-ray imaging that enables your doctor to locate nasal polyps and other abnormalities associated with chronic inflammation. It's also important in helping your doctor rule out the presence of other possible obstructions in the nasal cavity, such as a cancerous growth.
- Allergy tests. Your doctor may suggest allergy skin tests to determine if allergies are contributing to chronic inflammation. With a skin prick test, tiny drops of allergy-causing agents (allergens) are pricked into the skin of your forearm or upper back. The drops are left on your skin for 15 minutes before your doctor or nurse observes your skin for signs of allergic reactions. If a skin test cannot be performed, your doctor may order a blood test that screens for specific antibodies to various allergens.
- Test for cystic fibrosis. If you have a young child diagnosed with nasal polyps, your doctor may suggest testing for cystic fibrosis, an inherited condition affecting the glands that produce mucous, tears, sweat, saliva and digestive juices. The standard diagnostic test for cystic fibrosis is a noninvasive sweat test, which measures the amount of sodium and chloride in your child's perspiration.