Causes and Risk Factors of Nasal Polyps

Though nasal polyps are common, researchers are still in the process of determining the specific causes of these noncancerous growths.

Genetics may play a role in the development of nasal polyps, along with having other health conditions involving inflammation of tissue and/or the upper respiratory tract, like chronic rhinosinusitis and allergic rhinitis (hay fever).

What Are Nasal Polyps?

Nasal polyps are soft, swollen, abnormal, sac-like growths that line the inside of a person's nose or sinuses. They are often teardrop-shaped and grow together in groups on both sides of a person's nasal cavity. One-sided nasal polyps typically trigger further investigation, as they may be malignant nasal or sinus tumors.

Though nasal polyps themselves are not a form of cancer, it is possible for other growths to form in the nasal cavity that are cancerous—though they are not considered polyps. Frequently, nasal polyps grow where the sinuses open into the nasal cavity and can vary in size.

In general, nasal polyps are quite common, and anyone can develop them, though they tend to most frequently appear when a person is in their 30s and 40s.

Symptoms of Nasal Polyps

In some cases, people with nasal polyps don't experience any symptoms at all. For others, they may simply feel as though they have a normal (but never-ending) head cold or sinus infection. The symptoms of nasal polyps can include a combination of the following:

• Runny nose
• Stuffed up nose
• Sneezing
• Feeling like your nose is blocked
• Loss of smell
• Loss of taste
• Headache and pain if you also have a sinus infection
• Snoring
• Itching around the eyes
• Facial pain
• Dizziness
• Pain in the upper teeth
• Post-nasal drip
• Cough

Common Causes

Because the exact causes of nasal polyps are not yet known, it can be helpful to look at other conditions and symptoms that people with the growths tend to have. For instance, if a person has an underlying inflammation of tissue, they may be more likely to develop nasal polyps.

Frequently, the inflammation of the nose and sinus cavities are a result of chronic rhinosinusitis—which is a very common medical condition, affecting approximately 12% of adults worldwide.

Similarly, people who have the following conditions may also develop nasal polyps:

• Asthma
• Aspirin sensitivity
• Chronic sinus infections
• Cystic fibrosis
• Hay fever (allergic rhinitis)

There is research that suggests that people with nasal polyps may have an abnormal immune response and different chemical markers in their mucus membrane—which lines the sinuses and nasal cavity—in comparison to those who do not develop nasal polyps. These chemical markers act like signs and tell the body how to react to various stimuli. This is an area that scientists are actively investigating.

Genetics

The specific cause of nasal polyps is still unclear, but one theory is that they may be genetic—especially in cases involving genes that play a role in the immune system and inflammatory response. People may be more likely to develop nasal polyps if other members of their family also have them.

Lifestyle Risk Factors

There is no way to completely prevent nasal polyps of any size from forming, so no significant lifestyle adjustments will make a major difference.

The only thing that could potentially help keep them away is:

• Using nasal sprays
• Using antihistamines
• Getting allergy shots as needed

This could potentially help prevent the formation of large polyps that can block your airway.

A Word From Verywell

While there's really nothing you can do to prevent nasal polyps, if you have one of the conditions mentioned above—like asthma, hay fever, or chronic sinus infections—it's a good idea to pay close attention to your ability to breathe through your nose and talk to your healthcare provider right away if anything seems unusual. There are several different diagnostic tests the practitioner can run to help determine if you have nasal polyps and whether they need to be removed.