Nasal polyps are soft, noncancerous growths that develop in the lining of your nasal passages or sinuses. They form when chronic inflammation causes the tissue to swell, fill with fluid, and eventually droop down like small, tear-shaped sacs. Small polyps may go completely unnoticed, but larger ones or clusters can block your nasal passages enough to affect breathing, smell, and sleep. Roughly 1 in 4 people with chronic sinusitis develops nasal polyps, making them far more common than most people realize.
What Causes Them to Grow
Nasal polyps are driven by a specific pattern of inflammation known as type 2 inflammation. In this process, certain immune cells in the nasal lining release signaling molecules that attract a wave of other inflammatory cells, particularly eosinophils (a type of white blood cell associated with allergic reactions). These eosinophils accumulate in the tissue, causing it to swell with fluid, thicken, and eventually form the bulging growths we call polyps.
The process starts at the surface. Cells lining the nasal passages release an alarm signal that activates immune cells already sitting in the tissue. Those cells then pump out additional inflammatory signals that keep recruiting more eosinophils and sustaining the swelling. Meanwhile, structural cells called fibroblasts produce a protein that helps eosinophils migrate deeper into the tissue, reinforcing the cycle. This is why nasal polyps tend to persist and regrow: the underlying inflammation is self-reinforcing, not a one-time event.
What triggers this cycle in the first place isn’t always clear. Chronic sinus infections, allergies, asthma, and immune system quirks all play a role. Some people seem genetically predisposed to this type of inflammatory response. Nasal polyps aren’t caused by picking your nose, blowing too hard, or any single behavior.
Common Symptoms
Small nasal polyps often cause no symptoms at all. When polyps grow large enough or form in clusters, the most common complaints include:
- Persistent stuffiness that doesn’t respond to typical cold remedies
- Runny nose and mucus draining down the back of the throat (postnasal drip)
- Reduced or lost sense of smell, sometimes accompanied by dulled taste
- Facial pressure over the forehead and cheeks
- Snoring and disrupted sleep
- Frequent sinus infections
Loss of smell is one of the most distinctive and distressing symptoms. Unlike the temporary stuffiness of a cold, polyp-related smell loss can last months or years if untreated. It affects appetite, enjoyment of food, and even the ability to detect hazards like smoke or gas leaks.
Who Gets Nasal Polyps
Chronic sinusitis, the broader condition underlying most nasal polyps, affects roughly 11% of the European population. In the U.S., about 2% of adults meet full diagnostic criteria, though up to 13% report at least one chronic sinus symptom. Of all people with chronic sinusitis, 25% to 30% develop polyps.
Polyps are more common in adults over 40 and appear more frequently in men than women. Several conditions raise your risk significantly. Asthma is the most notable: people with both asthma and nasal polyps often have more severe disease on both fronts. Allergies, chronic sinus infections, and cystic fibrosis are also linked.
The Link to Aspirin Sensitivity and Asthma
A specific condition called aspirin-exacerbated respiratory disease (AERD) ties nasal polyps together with asthma and a sensitivity to aspirin or ibuprofen-type painkillers. Sometimes called Samter’s triad, AERD affects less than 1% of the general population but shows up in 10% to 20% of people with asthma. Among people who have both asthma and nasal polyps, the rate jumps to 30% to 40%.
People with AERD tend to have particularly stubborn polyps and sinus disease that is difficult to control with standard treatments. If you’ve noticed that aspirin or ibuprofen triggers breathing difficulties, facial flushing, or a sudden worsening of congestion, AERD is worth discussing with your doctor.
How Nasal Polyps Are Treated
Steroid Treatments
The first line of treatment is corticosteroids, which work by dialing down the inflammation that feeds polyp growth. Most people start with a steroid nasal spray, which is effective for mild cases and can shrink polyps over several weeks. For more significant polyps, steroid rinses delivered through high-volume saline irrigation appear to work better. In a randomized trial, patients using steroid irrigation saw roughly four times the polyp size reduction compared to those using a standard steroid spray over 12 weeks, with no effect on the body’s normal hormone levels.
Short courses of oral steroids can rapidly shrink polyps, but the side effects of long-term oral steroid use (weight gain, bone thinning, blood sugar changes) make them unsuitable as ongoing treatment.
Biologic Medications
For moderate to severe polyps that don’t respond well to steroids, a newer class of injectable medications called biologics targets the specific immune signals driving polyp growth. Three biologics are currently approved for nasal polyps: dupilumab (approved in 2019), omalizumab (2020), and mepolizumab (2021). Each blocks a different point in the inflammatory cascade.
Among these, dupilumab has shown the strongest results for restoring the sense of smell. A meta-analysis of clinical trials found that biologic treatments overall produced meaningful improvement in objective smell testing, with improvements detectable within the first 24 weeks. Dupilumab stood out with the largest effect, while mepolizumab showed little impact on smell specifically. These medications are given as injections, typically every two to four weeks, and are generally reserved for cases where other treatments have failed.
Surgery
When medications can’t adequately control symptoms, functional endoscopic sinus surgery (FESS) is the standard procedure. A surgeon works through the nostrils using a thin camera and specialized instruments that remove polyp tissue while preserving healthy nasal lining. The goal is to clear blocked drainage pathways and restore normal airflow. There are no external incisions, and most people go home the same day.
Surgery is effective. About 80% of patients achieve lasting symptom relief after a single procedure. Recovery typically involves a few weeks of congestion, crusting, and mild discomfort, with saline rinses to keep the healing tissue clean. Most people notice a dramatic improvement in breathing and smell within a month.
Recurrence After Treatment
The frustrating reality of nasal polyps is that they tend to come back. The surgery removes the growths, but the underlying inflammatory tendency remains. Roughly 30% of patients experience recurrence within five years, and that number climbs to about 66% at the ten-year mark. Up to 20% of surgical patients need a revision procedure within five to seven years.
This is why ongoing maintenance treatment matters. After surgery, most people continue using steroid rinses or sprays to suppress regrowth. For those with frequent recurrences, adding a biologic can significantly extend the polyp-free period. The combination of surgery to clear the initial burden followed by long-term medical therapy to prevent regrowth gives the best overall outcomes.
Impact on Sense of Smell
Smell loss is often what motivates people to seek treatment, and the good news is that it’s frequently reversible. Polyps physically block odor molecules from reaching the smell receptors high in the nasal cavity, and they also damage those receptors through chronic inflammation. Removing the polyps and calming the inflammation can restore smell, sometimes within weeks of starting treatment.
Biologic therapies have been particularly promising for smell recovery. Across clinical trials, patients treated with biologics showed moderate to large improvements on standardized smell tests, with the biggest gains appearing in the first 24 weeks. Longer treatment didn’t seem to add further improvement beyond that window, suggesting that the nerve recovery plateaus relatively early. For people who’ve lost their sense of smell for years, even partial recovery can be life-changing.