Chronic rhinosinusitis with nasal polyps is a long-lasting inflammatory condition that affects the nose and sinuses, causing soft growths to form in the nasal passages. This condition can make breathing difficult, reduce or eliminate the sense of smell, and significantly impact daily life.

Understanding the Scope of the Condition

Chronic rhinosinusitis with nasal polyps, often shortened to CRSwNP, is a condition that brings together two separate but related problems. The first part involves chronic rhinosinusitis, which means the tissues lining the nose and sinuses stay inflamed and irritated for at least 12 weeks, even with treatment attempts. The second part refers to nasal polyps, which are soft, painless growths that develop inside the nose or sinuses. These growths are not cancerous, but they can cause significant discomfort and breathing problems.^[1][2]

When someone has nasal polyps, these growths typically appear on both sides of the nose. They start small, resembling teardrops, but can grow larger over time until they look like peeled grapes. They usually originate from the ethmoid sinus, which is located between the eyes and nose. The polyps themselves are made of inflamed tissue and can range in color from pink to yellow or gray. While small polyps might not cause any noticeable symptoms, larger ones or clusters of polyps can block nasal passages completely, making it hard to breathe through the nose.^[3][4]

How Common Is This Condition?

Nasal polyps are estimated to occur in about 1 to 4 percent of people in the general population worldwide. However, when looking specifically at people who already have chronic rhinosinusitis, only about 20 to 30 percent will develop nasal polyps as part of their condition. This makes chronic rhinosinusitis with nasal polyps a distinct subset within the broader category of sinus inflammation.^[3][7][9]

The condition shows clear patterns in terms of who is most likely to develop it. Men are approximately twice as likely as women to develop nasal polyps. The typical age when people first develop chronic rhinosinusitis with nasal polyps is around 42 years, and most people receive their diagnosis when they are between 40 and 60 years old. This means the condition primarily affects middle-aged adults, though it can occur at other ages as well. As people get older, their overall risk of developing the condition increases.^[3][4]

What Causes Nasal Polyps to Develop?

Healthcare providers understand that inflammation is the driving force behind nasal polyps, but the exact reason why some people with inflammation develop polyps while others do not remains unclear. The inflammation itself can have several sources, but chronic sinusitis caused by allergies, infections, or asthma appears to be the most common trigger. When inflammation persists for three months or longer, it creates conditions where polyps can form and grow.^[4]

Research increasingly points to chronic rhinosinusitis with nasal polyps being an inflammatory disease rather than simply an infectious process. The condition is often driven by what scientists call type 2 inflammation. This particular type of inflammation involves the body’s immune system responding in specific ways, activating certain cells and releasing proteins that keep the inflammatory process going. The inflammation begins in the epithelium, which is the layer of cells that lines the inside of the nose and sinuses and serves as the first point of contact with everyday irritants like dust, pollen, and other environmental particles.^[5][7]

During this inflammatory process, cells in the epithelium release special signaling proteins called cytokines. Three key cytokines involved in nasal polyp formation are thymic stromal lymphopoietin (TSLP), interleukin-25 (IL-25), and interleukin-33 (IL-33). These cytokines can trigger multiple downstream inflammatory pathways, leading to various clinical problems including the formation of polyps and chronic symptoms like congestion and mucus production. Another important cytokine is interleukin-5 (IL-5), which promotes the production of eosinophils, a type of white blood cell that becomes elevated in many people with nasal polyps. These eosinophils contribute to ongoing inflammation and tissue damage.^[5][6]

Who Is at Higher Risk?

Several existing health conditions can increase someone’s likelihood of developing chronic rhinosinusitis with nasal polyps. Asthma is one of the strongest risk factors, and many people with nasal polyps also have asthma. In fact, the presence of nasal polyps can make asthma harder to control, and people with both conditions often experience more asthma-related emergency department visits and need more medication. The inflamed sinuses from nasal polyps can worsen asthma symptoms, creating a cycle where both conditions affect each other.^[2][7]

Allergic conditions also play a significant role. People with allergic rhinitis, commonly known as hay fever, face increased risk for developing nasal polyps. This makes sense because allergies cause ongoing inflammation in the nasal passages, which can eventually lead to polyp formation. Chronic sinus infections that keep recurring also raise the risk, as the constant inflammation provides the environment where polyps can grow.^[3][4]

Some people have a condition called aspirin sensitivity, where taking aspirin or other nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen triggers symptoms or makes nasal polyps worse. People with this sensitivity, called aspirin-exacerbated respiratory disease, are at particularly high risk for developing nasal polyps. Additionally, certain rare genetic conditions like cystic fibrosis significantly increase the likelihood of developing nasal polyps, with nearly all people who have cystic fibrosis eventually developing chronic rhinosinusitis.^[4][7]

Genetics may also play a broader role beyond specific inherited conditions. Certain gene mutations or variations can influence how nasal tissues react to inflammation, potentially making some people more susceptible to developing polyps when exposed to inflammatory triggers. However, no single genetic or environmental factor has been strongly and consistently linked to the development of the condition across all cases.^[3][4]

Recognizing the Symptoms

Small nasal polyps might not cause any noticeable symptoms at all, and some people don’t even know they have them. However, as polyps grow larger or form in groups, they begin to block the nasal passages and sinuses, leading to a range of uncomfortable symptoms. The most common symptom is a stuffy or runny nose that persists despite typical cold or allergy treatments. Unlike a temporary cold, this congestion doesn’t go away after a week or two.^[2][8]

Many people with nasal polyps experience a reduced or complete loss of their sense of smell, a condition called hyposmia when partial and anosmia when total. A significant proportion of people with chronic rhinosinusitis with nasal polyps experience complete anosmia. This loss of smell doesn’t just affect the enjoyment of food; it can also pose safety risks because the person cannot detect important warning signs like smoke from a fire, gas leaks, or spoiled food. The loss of smell often comes with a reduced ability to taste as well, since smell plays a crucial role in how we perceive flavors.^[2][19]

Facial pressure or pain is another frequent complaint. People often describe feeling pressure around the forehead, cheeks, nose, and between the eyes. This sensation comes from the blocked sinuses and inflamed tissues. The pressure can sometimes extend to the upper teeth, causing tooth pain without any dental problems. Postnasal drip, where mucus runs down the back of the throat, is also very common and can be particularly bothersome. This excess mucus can lead to frequent throat clearing, coughing, and an unpleasant sensation in the throat.^[2][8]

Additional symptoms can include headaches, snoring, and difficulty sleeping. The blocked nasal passages force people to breathe through their mouths, especially at night, which can lead to dry mouth, sore throat upon waking, and disturbed sleep. Some people develop sleep apnea, a condition where breathing repeatedly stops and starts during sleep, when their polyps become large enough to significantly obstruct airflow. The combination of poor sleep, difficulty breathing, and constant symptoms can lead to chronic fatigue and reduced energy during the day.^[4][8]

According to national surveys, many people with nasal polyps experienced significant delays in diagnosis, often because their symptoms overlapped with or were mistaken for asthma or allergies. The diagnosis often came only after they connected with a specialist such as an ear, nose, and throat doctor (ENT specialist or otolaryngologist) or an allergist who could perform the necessary testing.^[5]

How to Prevent or Reduce Risk

While there is no guaranteed way to prevent chronic rhinosinusitis with nasal polyps, especially in people with genetic predispositions, certain strategies can help reduce the risk or keep existing polyps from getting worse. Managing underlying conditions like asthma and allergies is crucial. When these conditions are well-controlled with appropriate medications and lifestyle adjustments, the overall inflammation in the airways may be reduced, potentially slowing or preventing polyp development.^[2]

Avoiding triggers that can irritate the nasal passages and worsen inflammation is an important preventive strategy. Tobacco smoke is one of the most significant irritants and should be avoided entirely. For people with aspirin sensitivity, avoiding aspirin and NSAIDs like ibuprofen and naproxen sodium is essential. Other irritants to avoid include incense, strong chemical fumes, and excessive dust or debris. Taking steps to improve indoor air quality, such as using air filters and maintaining proper ventilation, can also help reduce exposure to airborne irritants.^[2][11]

Good nasal hygiene can support sinus health. Using saline (saltwater) nasal sprays or rinses helps keep the nasal passages moist and clear of irritants and thick mucus. These rinses can be done with store-bought saline sprays or with a device called a neti pot that allows people to flush their nasal passages with a saltwater solution. When using a neti pot, it’s important to use distilled, sterile, or previously boiled and cooled water to avoid introducing harmful organisms into the sinuses. The neti pot should be rinsed and thoroughly dried after each use.^[2][11]

Prompt treatment of respiratory infections and sinus infections can prevent acute problems from becoming chronic. When infections are treated early and completely, they are less likely to cause the long-term inflammation that can lead to polyp formation. Regular check-ups with healthcare providers can help catch developing problems early when they are easier to manage.^[7]

How the Condition Affects the Body

In a healthy nose and sinus system, the tissues are covered with a thin layer of mucus that traps dust, germs, and other particles. Tiny hair-like structures called cilia constantly move this mucus along, sweeping it toward the throat where it can be swallowed and neutralized by stomach acid. This system, called mucociliary clearance, keeps the airways clean and protected. The sinuses, which are hollow spaces in the bones around the nose, normally drain their mucus into the nasal passages through small openings.^[7]

When chronic rhinosinusitis with nasal polyps develops, several things go wrong in this system. The inflammation causes the tissues lining the nose and sinuses to swell significantly. This swelling narrows or completely blocks the small openings through which the sinuses normally drain. When these passages are blocked, mucus cannot flow properly and becomes trapped in the sinuses. The trapped mucus creates a moist environment where bacteria can grow, potentially leading to secondary infections.^[7]

The nasal polyps themselves add to the blockage problem. As these soft growths develop and enlarge, they take up space in the nasal passages, further restricting airflow and mucus drainage. The combination of swollen tissues and physical obstruction from polyps creates a cycle where poor drainage leads to more inflammation, which causes more swelling and potentially more polyp growth. The impaired mucociliary clearance means irritants and allergens stay in contact with the nasal tissues longer, perpetuating the inflammatory response.^[3]

At the cellular level, chronic rhinosinusitis with nasal polyps involves complex immune system changes. The epithelial cells lining the nose become damaged and don’t function as effectively as a barrier. They release cytokines that recruit inflammatory cells, particularly eosinophils, to the area. These eosinophils release substances that can damage tissue and keep inflammation going. The tissue becomes infiltrated with fluid, immune cells, and inflammatory proteins, which is what forms the visible polyp. The polyp tissue is essentially swollen, inflamed mucous membrane that has protruded into the nasal cavity.^[5]

The inflammation can affect the olfactory region at the top of the nasal cavity, where smell receptors are located. When this area is inflamed and covered with mucus or blocked by polyps, odor molecules cannot reach the smell receptors, resulting in reduced or lost sense of smell. Additionally, chronic inflammation can lead to changes in the bone remodeling around the sinuses, sometimes causing permanent structural changes visible on imaging scans.^[3]

For people who have both nasal polyps and asthma, the connection between the upper and lower airways becomes clinically important. The inflammation in the sinuses can influence inflammation in the lungs, making asthma symptoms worse. Bacterial organisms from the sinuses can potentially serve as a reservoir that seeds infections in the lungs, particularly in people with other lung conditions like cystic fibrosis.^[7]