The most common signs of a sinus infection are thick, discolored nasal discharge, facial pain or pressure, a stuffy nose, and a reduced sense of smell. These symptoms overlap heavily with a regular cold, so the key distinction is how long they last and whether they get worse. Most sinus infections start as viral colds that don’t resolve within the expected timeframe.
Primary Symptoms to Watch For
A sinus infection, known medically as sinusitis, produces a recognizable cluster of symptoms. The core signs include:
- Thick, cloudy, or colored nasal discharge (yellow, green, or gray)
- Nasal congestion that blocks one or both sides of your nose
- Facial pressure or pain around your cheeks, forehead, or between your eyes
- Reduced or lost sense of smell and taste
Beyond these hallmark signs, sinus infections commonly cause headaches, fatigue, bad breath, ear pressure or pain, and even upper tooth pain. The toothache catches many people off guard, but it happens because the roots of your upper molars sit very close to your maxillary sinuses. When those sinuses swell, the pressure pushes directly against the tooth roots.
Facial pain tends to worsen when you bend forward, and congestion is often worse on one side. Pain concentrated on one side of the face, or tenderness when you press on the cheek below one eye, is particularly suggestive of a sinus infection rather than a simple cold.
How Long Symptoms Last Matters
Doctors classify sinus infections by duration, and the category affects both what’s causing it and how it’s treated. Acute sinusitis lasts less than four weeks. Subacute sinusitis runs four to twelve weeks. Chronic sinusitis persists beyond twelve weeks.
Most acute sinus infections are viral, meaning they’re essentially colds that have inflamed the sinus passages. A typical cold improves within seven to ten days. If your symptoms haven’t improved after ten days, or if they’re getting noticeably worse after five to seven days, that timeline shift is what separates a lingering cold from a sinus infection that may need treatment.
Chronic sinusitis involves a different process. Diagnosing it requires not just persistent symptoms but objective evidence of inflammation, typically confirmed through a nasal endoscopy or CT scan showing thickened or opaque sinus tissue. Some people with chronic sinusitis also develop nasal polyps, which are soft, noncancerous growths inside the sinuses that further block drainage.
Viral vs. Bacterial: How to Tell the Difference
This is the question most people are really asking, because it determines whether antibiotics would help. The honest answer is that it’s difficult to tell from symptoms alone, but a few patterns point toward a bacterial infection.
Four signs are the most useful predictors of bacterial sinusitis: thick, discolored nasal discharge, facial or tooth pain concentrated on one side, tenderness over one cheek, and the pattern called “double sickening.” Double sickening means you started to feel better, then got worse again. That rebound pattern has reasonable accuracy for identifying bacterial infections, picking them up about 72% of the time.
One thing that does not reliably distinguish bacterial from viral infections is the color of your mucus. Green or yellow discharge is widely assumed to mean bacteria, but both viral and bacterial infections change mucus color in similar ways. The color comes from enzymes released by your white blood cells as they fight the infection, regardless of the type of invader. Taking antibiotics based on mucus color alone is not supported by evidence.
The general guideline is that bacterial sinusitis becomes more likely when symptoms persist beyond ten to fourteen days without improvement, when symptoms worsen after an initial five-to-seven-day improvement, or when symptoms are unusually severe from the start (high fever with intense facial pain and heavy discharge).
Sinus Pressure vs. Migraine
Many people who think they have recurring sinus headaches actually have migraines. True sinus headaches, caused by active sinus inflammation, are relatively rare. The defining feature of a genuine sinus headache is thick, discolored nasal discharge accompanying the pain. If you have pressure around your forehead and cheeks but your nose is clear, a migraine is a more likely explanation.
Migraines can cause nasal congestion and even a runny nose, which adds to the confusion. But migraine-related nasal symptoms produce thin, clear discharge rather than the thick, opaque mucus of a sinus infection. If you’ve been treating “sinus headaches” with decongestants for years without much relief, it may be worth exploring whether migraines are the real cause.
Signs in Children
Sinus infections look somewhat different in kids than in adults. In younger children, the primary signs are a runny nose that lasts longer than seven to ten days, thick green or yellow discharge (though it can also be clear), and a cough that’s worse at night. Daytime coughing may come and go. Swelling around the eyes is another signal.
One important difference: children under five rarely complain of headaches with sinus infections, even though headache is a hallmark symptom in adults. Young kids are more likely to seem generally irritable or fatigued without being able to pinpoint where they hurt. If a child’s cold symptoms haven’t improved after ten days, or they develop a fever after several days of what seemed like a normal cold, those are the same “double sickening” red flags that apply to adults.
Warning Signs That Need Urgent Attention
Sinus infections very rarely become dangerous, but when they do, the infection has typically spread to the eye socket or, in extreme cases, toward the brain. The sinuses sit directly behind the eyes and beneath the skull, so a severe infection can cross those boundaries.
Early signs of spread to the eye area include swelling and redness around one eye, pain when moving the eye, or the eye appearing to bulge forward. More advanced spread causes changes in vision, particularly a reduced ability to distinguish red or green colors. That color perception change is actually an early warning that pressure is building around the optic nerve, and it can appear before you notice significant vision loss.
Any combination of high fever, severe headache, swelling around the eye, vision changes, confusion, or a stiff neck during a sinus infection warrants immediate medical evaluation. These complications are uncommon, but they progress quickly when they do occur.