Chronic sinusitis is persistent inflammation of the sinuses lasting 12 weeks or longer, even with treatment attempts. It affects roughly 12% of the adult U.S. population in any given year, making it one of the most common long-term health conditions. Unlike a sinus infection that clears up in a week or two, chronic sinusitis lingers, cycling between better and worse stretches that can significantly erode quality of life.
How It Differs From a Regular Sinus Infection
A typical sinus infection (acute sinusitis) follows a cold, lasts one to four weeks, and resolves on its own or with a short course of antibiotics. Chronic sinusitis is a different condition. The inflammation persists for at least 12 consecutive weeks, and the underlying problem is less about a single infection and more about an immune or structural issue that keeps the sinuses inflamed. Some people experience distinct flare-ups on top of a constant baseline of congestion and pressure, while others feel roughly the same level of misery every day.
Common Symptoms
The hallmark symptoms overlap with those of a short-term sinus infection, but they don’t go away:
- Nasal congestion or obstruction that makes breathing through your nose difficult on one or both sides
- Thick, discolored nasal discharge that may drain down the back of the throat (postnasal drip)
- Facial pain or pressure concentrated around the cheeks, forehead, or between the eyes
- Reduced sense of smell and taste, which can range from mild dulling to a near-complete loss
Fatigue is extremely common, partly from poor sleep caused by congestion and partly from the body’s ongoing inflammatory response. Ear fullness, bad breath, upper tooth pain, and a persistent cough (especially at night) round out the picture for many people.
What Causes It
The causes of chronic sinusitis are multifactorial. There’s rarely one neat explanation. Instead, a combination of systemic, local, and environmental factors converge to keep the sinuses inflamed.
Structural issues play a role in many cases. A deviated nasal septum, narrow sinus drainage pathways, or scarring from a previous surgery can physically block mucus from draining the way it should. When mucus pools, it creates an environment where inflammation feeds on itself.
Immune and inflammatory problems are often central. Some people have a type of immune overreaction (called Type 2 inflammation) that drives tissue swelling and polyp growth inside the sinuses. Conditions like asthma, allergies, and aspirin sensitivity frequently overlap with chronic sinusitis for this reason. Genetic diseases like cystic fibrosis and various immunodeficiency conditions also predispose people to chronic sinus inflammation.
Environmental and microbial factors add another layer. Bacteria and fungi can form biofilms on sinus tissue, essentially building a protective shield that makes them extremely difficult to eradicate with standard antibiotics. Air pollution, cigarette smoke, and ongoing allergen exposure all contribute to keeping the sinuses irritated.
With Polyps vs. Without Polyps
Doctors have traditionally divided chronic sinusitis into two categories: cases with nasal polyps and cases without them. Nasal polyps are soft, painless growths that develop on the lining of the sinuses or nasal passages. They tend to form when Type 2 inflammation is the dominant driver, and they’re associated with more severe loss of smell, more frequent recurrence after treatment, and a stronger link to asthma.
Cases without polyps may involve more pain and pressure as primary complaints, and the underlying inflammation often works through different immune pathways. That said, the medical community increasingly recognizes that this binary split is too simple. Newer classification systems look at the specific type of inflammation present rather than just whether polyps exist, because two people with polyps can have very different immune profiles and respond to very different treatments.
How It’s Diagnosed
Diagnosis starts with your symptoms and their duration, but symptoms alone aren’t enough. Doctors need to see objective evidence of sinus inflammation, and they have two main tools for that.
Nasal endoscopy involves threading a thin, flexible tube with a camera into your nasal passages. It takes about a minute, feels odd but is rarely painful, and lets your doctor look directly at the sinus openings for swelling, polyps, or discharge. This is typically the first step.
A CT scan of the sinuses provides a detailed cross-sectional view and is the most reliable imaging technique for determining whether sinuses are obstructed. It can reveal thickened sinus membranes, fluid-filled sinuses, and the specific pattern of which sinuses are affected. CT scans are generally reserved for cases that don’t respond to initial treatment, or when surgery is being considered. Allergy testing may also be recommended to identify contributing triggers.
First-Line Treatments
Medical management comes before any surgical discussion, and two therapies form the foundation.
Saline nasal irrigation is consistently recommended as a starting treatment. This means physically flushing the nasal passages with a saltwater solution, typically using a squeeze bottle or neti pot. High-volume irrigation (using a full 240 mL bottle per side) works better than low-volume sprays because it reaches deeper into the sinus cavities. Isotonic saline (matching your body’s salt concentration) is the standard recommendation, balancing effectiveness with comfort and cost. Use distilled or bottled water. If you use tap water, boil it for at least five minutes and let it cool first, since rare but serious infections have been linked to unsterilized tap water in nasal rinses. Room temperature works well, though warming the solution to around 40°C (104°F) is fine if you prefer it. Clean your irrigation device by boiling it for at least two minutes between uses.
Topical nasal corticosteroid sprays are the other pillar. These reduce inflammation directly in the sinus lining, and unlike oral steroids, they work locally with minimal absorption into the rest of your body. For some patients, particularly after surgery, steroid solutions can be added to the saline irrigation itself. Studies show this approach is safe and doesn’t raise the risk of elevated eye pressure or other systemic steroid side effects.
Oral steroids are sometimes prescribed for short bursts to knock down severe inflammation, especially when polyps are blocking the nasal passages. Antibiotics may be used during acute flare-ups, but because chronic sinusitis is fundamentally an inflammatory condition rather than a simple infection, long-term antibiotics are not a standard approach.
When Surgery Becomes an Option
When several months of consistent medical treatment fails to provide adequate relief, endoscopic sinus surgery is the next step. The procedure is performed entirely through the nostrils with no external incisions. A surgeon uses a small camera and specialized instruments to widen the natural drainage pathways of the sinuses, remove polyps, and clear out diseased tissue.
The results can be substantial. Quality-of-life improvements typically become noticeable within six months of surgery and, based on long-term follow-up data, often persist for nearly 11 years. Surgery doesn’t cure the underlying inflammatory tendency, so most people still need ongoing nasal irrigation and topical steroids afterward. But by opening up the sinuses, surgery makes those medical treatments far more effective because sprays and rinses can actually reach the tissue they’re meant to treat.
Biologic Therapies for Severe Cases
For people with chronic sinusitis and nasal polyps driven by Type 2 inflammation, a newer class of injectable medications has changed the treatment landscape. These biologics target specific proteins in the immune system that fuel the overactive inflammatory response. Three biologics are currently approved for chronic sinusitis with nasal polyps, and a fourth is available for patients who also have severe eosinophilic asthma.
These treatments are typically reserved for people whose polyps keep returning despite surgery and standard medical therapy. They’re given as injections every two to four weeks and can dramatically shrink polyps, restore the sense of smell, and reduce the need for repeat surgeries. They don’t work for every subtype of chronic sinusitis, which is one reason identifying the specific pattern of inflammation matters.
Potential Complications
Chronic sinusitis is uncomfortable and disruptive, but it can also lead to rare, serious complications if inflammation spreads beyond the sinuses. The eye sockets sit immediately next to the sinuses, and orbital involvement accounts for about 80% of all sinusitis complications. Signs include worsening eye swelling, redness, pain with eye movement, or vision changes. Left untreated, this can progress to optic nerve damage or dangerous blood clot formation in the veins near the brain.
Intracranial complications occur in roughly 4% of complicated sinusitis cases. The blood vessels connecting the sinuses to the brain lack valves, which means infection from inflamed sinus tissue can travel directly into the skull cavity. These scenarios are rare, but they underscore why persistent, worsening symptoms, especially sudden severe headache, high fever, or visual disturbances, warrant prompt medical evaluation.