Sinusitis shows up as a combination of facial swelling, discolored nasal discharge, and puffiness around the eyes and cheeks. Some of these signs are obvious in the mirror, while others only become visible on a CT scan or when a doctor looks inside your nose with a small camera. Here’s what sinusitis actually looks like at every level, from what you see on your own face to what shows up on imaging.
What You See in the Mirror
The most noticeable external sign of sinusitis is swelling and puffiness around the eyes, cheeks, nose, and forehead. This swelling tends to get worse when you bend over because the pressure in your inflamed sinuses increases with gravity. In some cases the skin over the affected sinus looks slightly flushed or feels warm to the touch, though dramatic redness is uncommon in a straightforward sinus infection.
Children often show these signs more prominently. Swelling around the eyes is a hallmark of pediatric sinusitis, and it’s frequently worse in the morning after a night of lying flat. Kids may also develop persistent dark circles under the eyes (sometimes called “allergic shiners”), though these overlap with allergies and aren’t unique to sinus infections. Chronic mouth breathing and a perpetually stuffy appearance are other visual clues in younger children who can’t describe their symptoms well.
What Your Mucus Tells You
Nasal discharge is probably the single most visible indicator of sinusitis, and its color shifts as the infection progresses. Clear mucus is normal or allergy-related. White mucus means your nasal tissues are swollen and congested, slowing the flow of mucus so it loses moisture and turns thick and cloudy. Yellow mucus signals that your immune system is actively fighting an infection, with white blood cells rushing to the site and then being swept out. Green, thick mucus means those white blood cells have piled up in large numbers. If you’re still producing green discharge after 10 to 12 days, that pattern points toward bacterial sinusitis rather than a simple cold.
One important caveat: mucus color alone doesn’t reliably distinguish a viral infection from a bacterial one. The better indicator is how long you’ve been sick and how your symptoms are trending. A cold that seems to improve and then worsens again around day seven, or one that simply never gets better after 10 days, is more suggestive of bacterial sinusitis than the shade of green in your tissue.
What a Doctor Sees Inside Your Nose
When a doctor examines your nasal passages with an endoscope (a thin, lighted tube), the view is strikingly different from a healthy nose. Normally, the nasal lining is a pale pink with a thin, clear coat of mucus. With sinusitis, the mucosa turns red and swollen, sometimes so puffy that it blocks the narrow drainage channels where your sinuses empty into your nasal cavity. Thick, discolored secretions pool around these openings, particularly near the middle part of the nasal sidewall where several sinuses converge.
Doctors look for specific things during this exam: the color of the lining (pale versus inflamed red), whether mucus is thin or thick and purulent, and whether nasal polyps are present. Polyps are smooth, grape-like growths that hang from the sinus lining. They’re a hallmark of chronic sinusitis and can range from small bumps tucked under a fold of tissue to large masses that extend well into the nasal cavity. Their presence, along with the type of drainage and degree of tissue swelling, helps distinguish chronic sinusitis from an acute episode.
What Shows Up on a CT Scan
CT scans offer the clearest picture of what’s happening inside the sinuses themselves, since the sinuses sit behind bone and can’t be seen directly. In a healthy scan, the sinus cavities appear as dark, air-filled spaces. With sinusitis, three main findings stand out.
- Mucosal thickening: The lining of the sinus swells inward, appearing as a gray band along the sinus walls. This shows up in over 90 percent of sinusitis cases, though it’s common enough in people with ordinary colds that it isn’t very specific on its own. Thickening greater than 4 millimeters is considered significant.
- Air-fluid levels: A horizontal line inside the sinus where trapped fluid meets the remaining air pocket above it. This is a more reliable sign of active infection.
- Complete opacification: The entire sinus appears gray or white instead of black, meaning it’s completely filled with swollen tissue, fluid, or both. This is the most dramatic-looking finding.
Air-fluid levels and complete opacification are more specific for sinusitis but only appear in about 60 percent of cases. Interestingly, one study found that even people with ordinary cold symptoms frequently showed sinus abnormalities on CT, with maxillary sinus changes in 87 percent and ethmoid sinus changes in 65 percent of patients. This is why doctors don’t order CT scans for routine sinus infections. The scan would look abnormal in almost everyone with a cold, making it hard to tell a normal viral process from sinusitis that needs treatment.
Acute Versus Chronic: How They Differ
Acute sinusitis (lasting up to four weeks) tends to look more “active” on both exam and imaging. You’ll see thick, discolored drainage, red and swollen tissue, and sometimes visible air-fluid levels on a scan. The facial swelling and tenderness are usually more pronounced, and the whole picture looks like an infection in full swing.
Chronic sinusitis (symptoms lasting more than 12 weeks) looks different. The nasal lining may be thickened and boggy rather than acutely red. Polyps are far more common. On CT, you’re more likely to see persistent mucosal thickening and partially or fully opacified sinuses rather than the sharp air-fluid lines of an acute infection. The external signs tend to be subtler too: mild persistent puffiness rather than obvious swelling, and ongoing congestion rather than the dramatic facial pressure of an acute episode.
Fungal Sinusitis Has a Distinct Look
Fungal sinus infections are uncommon but have a very distinctive appearance. The most common type, allergic fungal sinusitis, produces thick, sticky mucus with a characteristic peanut-butter-like or clay-like consistency. Under a microscope, this mucus contains large numbers of a specific immune cell (eosinophils) along with scattered fungal fragments. Unlike invasive fungal infections, the fungus in allergic fungal sinusitis doesn’t burrow into the tissue. It sits in the mucus and triggers an intense allergic reaction that causes the sinuses to fill with this dense material.
On CT, allergic fungal sinusitis often looks more dramatic than bacterial sinusitis, with multiple sinuses completely filled and sometimes expanded. The dense mucus can appear bright on certain scan settings because of its high protein and mineral content, which helps distinguish it from ordinary bacterial infections.
Warning Signs That Look Different
Most sinusitis looks unpleasant but not alarming. The visual signs that signal something more serious involve the eyes. If a sinus infection spreads to the tissue around the eye socket (orbital cellulitis), you may notice significant eyelid swelling, redness or discoloration of the skin around the eye, and in more advanced cases, the eye itself may bulge forward or become difficult to move. Vision changes, double vision, or pain with eye movement alongside sinus symptoms are signs of a complication that needs immediate medical attention. This is especially important in children, where the thin bone separating the sinuses from the eye socket makes spread more likely.