A nasal endoscopy can detect a wide range of conditions, from nasal polyps and chronic sinus infections to tumors, structural problems, and cerebrospinal fluid leaks. The procedure takes one to five minutes, uses a thin flexible scope inserted through the nostril, and gives your doctor a real-time, magnified view of tissues that can’t be seen during a standard exam. It’s one of the most accurate first-line tools for evaluating the nasal passages, with a diagnostic accuracy of about 95% when compared to CT imaging for chronic sinusitis.
Polyps and Growths
Nasal polyps are one of the most common findings. These are soft, noncancerous growths that develop on the lining of the nasal passages or sinuses, often triggered by chronic inflammation from allergies, asthma, or recurring infections. During endoscopy, polyps are graded by location and size: small polyps confined to the middle part of the nasal passage are scored differently from larger ones that extend beyond it. This grading helps your doctor track whether polyps are growing, shrinking with treatment, or need surgical removal.
The scope can also identify more concerning growths. Tumors of the nasal cavity, paranasal sinuses, orbit, or skull base can all be visualized and biopsied during the same procedure. In children, a rare but important growth called a juvenile nasopharyngeal angiofibroma (a blood vessel tumor) is sometimes discovered this way. Catching these early changes the treatment timeline significantly.
Chronic Sinusitis and Infections
Chronic sinusitis is probably the single most common reason doctors order a nasal endoscopy. The scope lets them see swelling, redness, and discharge directly at the sinus openings, which are hidden from view in a regular office exam. Discharge is categorized by type: thin and clear suggests ongoing inflammation, while thick and pus-like points toward active bacterial infection. This distinction matters because it changes whether you need antibiotics, steroids, or a different approach entirely.
The endoscopy also reveals fungal sinusitis, which can look quite different from bacterial infections. Allergic fungal sinusitis produces thick, dark, peanut-butter-like mucus, while invasive fungal infections cause tissue damage that’s visible on the scope. Both require different treatment strategies than standard sinus infections.
When compared head-to-head with CT scans for diagnosing chronic sinusitis, nasal endoscopy has a sensitivity of about 96% and a specificity of 83%. That means it catches nearly all true cases, though it occasionally flags inflammation that turns out to be less significant on imaging. Many doctors use both tools together for a complete picture.
Structural Abnormalities
A deviated septum, where the wall between your nostrils is shifted to one side, is easily spotted on endoscopy. While mild deviations are common and harmless, severe ones can block airflow and trap mucus, leading to recurring infections. The scope shows exactly where and how much the septum is displaced, which helps plan a correction surgery (septoplasty) if needed.
Turbinate hypertrophy is another frequent finding. Your turbinates are bony ridges lined with tissue inside each nostril that warm and humidify the air you breathe. Allergies, chronic irritation, or infection can cause them to swell permanently, narrowing the airway. Endoscopy confirms whether your congestion is from swollen turbinates, polyps, a deviated septum, or some combination, which determines whether medication or a turbinate reduction procedure is the right next step.
Cerebrospinal Fluid Leaks
One of the more serious findings a nasal endoscopy can detect is a cerebrospinal fluid (CSF) leak, where the fluid that cushions the brain and spinal cord drips through a defect in the skull base and exits through the nose. This can happen after head trauma, surgery, or spontaneously. On endoscopy, signs include a glistening appearance of the nasal lining or visible clear fluid dripping from a specific spot. The findings can be subtle and are sometimes nonspecific, so additional tests like collecting the fluid for analysis are often needed to confirm the diagnosis. But the scope is valuable for narrowing down which side the leak is on and, in some cases, pinpointing the exact location.
Smell Loss and Nasal Blockages
If you’ve lost your sense of smell, a nasal endoscopy is a standard part of the workup. The scope checks whether a physical blockage, like polyps, swollen tissue, or a mass, is preventing odor molecules from reaching the smell receptors high in your nasal cavity. This is an important distinction: blockage-related smell loss often improves with treatment (removing polyps or reducing inflammation), while nerve-related smell loss from a virus or head injury requires a different approach. Knowing which type you have determines your prognosis and treatment plan.
What Doctors Look for in Children
Nasal endoscopy is used in children for many of the same reasons as adults, but a few findings are especially relevant in younger patients. Enlarged adenoids (adenoid hypertrophy) are a common cause of nasal obstruction and snoring in kids, and the scope gives a direct view of how much of the airway they’re blocking. Foreign objects lodged in the nose, a surprisingly common problem in toddlers, are also quickly identified and sometimes removed during the same procedure.
In children with cystic fibrosis, immune deficiency disorders, or ciliary dyskinesia (a condition where the tiny hairs lining the airways don’t move properly), nasal endoscopy helps monitor for polyps and sinus infections that tend to recur. It’s also used when asthma is worsening alongside sinus symptoms, since untreated sinus disease can make asthma harder to control.
How Findings Are Scored and Tracked
Doctors don’t just describe what they see in general terms. They use a standardized scoring system called the Lund-Kennedy scale that rates five specific features on each side of the nose: polyps, discharge, swelling, scarring, and crusting. Each feature gets a score from 0 (absent) to 2 or 3 (severe), with a maximum total score of 20. This scoring is done at your initial visit and then repeated at follow-ups, typically at 3, 6, 12, 24, and 36 months after treatment or surgery. The numbers make it easy to track whether you’re improving, stable, or getting worse over time.
What the Procedure Feels Like
The entire exam takes one to five minutes and happens in a regular office visit, not an operating room. Before the scope goes in, a decongestant spray reduces swelling in your nasal passages, and a numbing spray keeps you comfortable. You’re fully awake the entire time. Most people describe a sensation of pressure or mild discomfort but not pain. There’s no recovery period, and you can go about your day immediately afterward. Minor nosebleeds can occur but are uncommon. Some people feel lightheaded briefly, which passes quickly.
The scope itself is thin and flexible, with a light and camera at the tip. Your doctor can angle it to examine the middle meatus (the main drainage pathway for your sinuses), the back of the nasal cavity near the adenoids, and the openings of the individual sinuses. If something abnormal is spotted, a small tissue sample can be taken through the scope for biopsy during the same visit.