The hallmark signs of a sinus infection are thick, discolored nasal discharge combined with nasal congestion, facial pain or pressure, and a reduced sense of smell. These four symptoms are the cardinal indicators used to diagnose sinusitis, and most people experience at least two or three of them. What separates a sinus infection from a regular cold is how long these symptoms last and whether they worsen over time rather than gradually improving.
The Core Symptoms
Sinus infections produce a recognizable cluster of symptoms centered around your sinuses, the air-filled cavities behind your forehead, cheeks, and eyes. The most common signs include:
- Thick, discolored nasal discharge: Yellow or green mucus draining from the front of your nose or down the back of your throat (postnasal drip).
- Nasal congestion: A blocked or stuffy feeling that makes breathing through your nose difficult.
- Facial pain and pressure: A deep, aching sensation around your cheeks, forehead, or between your eyes that often worsens when you bend forward.
- Reduced sense of smell: A noticeable drop in your ability to smell, sometimes accompanied by dulled taste.
Beyond these four primary signs, sinus infections frequently cause headaches, bad breath, fatigue, and a cough that tends to be worse at night due to mucus draining down the throat. One symptom that catches people off guard is upper tooth pain. Your largest sinuses sit directly above the roots of your upper back teeth, and when those sinuses become inflamed, the pressure can radiate into nearby teeth. This pain affects multiple upper teeth at once rather than a single tooth, which helps distinguish it from an actual dental problem.
Fever can occur but isn’t always present. When it does appear with a sinus infection, it’s typically above 100.4°F (38°C) and tends to accompany more severe cases.
Sinus Infection vs. a Common Cold
Every sinus infection starts out looking like a cold, which is why timing matters more than any single symptom. A cold typically improves within seven days. A sinus infection either persists beyond 10 days without getting better, or it follows a distinctive pattern called “double sickening.”
Double sickening is one of the most reliable clues that a sinus infection has developed. It works like this: you catch a cold, start feeling better around day five, and then suddenly get worse again. Your congestion returns, the facial pressure intensifies, and you may develop a new fever. This worsening after an initial improvement strongly suggests a bacterial sinus infection has taken hold on top of the original viral illness.
Color of mucus alone is not a reliable way to tell the difference. Yellow or green discharge happens with ordinary colds too, typically appearing around day three or four. The same goes for headaches and even bad breath. Doctors cannot distinguish viral from bacterial sinusitis based on a single office visit or any one symptom. The pattern over time is what matters.
Three Patterns That Point to a Bacterial Infection
Doctors look for one of three specific scenarios to diagnose a bacterial sinus infection:
- Persistent symptoms: Nasal discharge, congestion, or facial pain lasting 10 days or more with no improvement.
- Double sickening: Symptoms that improve, then worsen again within 10 days of initially getting sick.
- Severe onset: High fever (above 100.4°F) combined with thick, discolored discharge and significant facial pain lasting at least three to four consecutive days.
Most sinus infections are viral and resolve on their own. Only when one of these three patterns emerges do antibiotics become relevant. If your symptoms are bothersome but steadily improving, you’re likely dealing with a viral infection that will clear without treatment.
Signs in Children
Children get sinus infections too, but their symptoms can look different from what adults experience. Kids are less likely to report facial pressure and more likely to show general irritability, reduced appetite, and a persistent cough. The key signs to watch for in children include cold symptoms (runny nose, daytime cough, or both) that last more than 10 days without improving, thick yellow nasal discharge with a fever persisting three or four days, and swelling or dark circles around the eyes, particularly in the morning.
A severe headache behind or around the eyes that gets worse when your child bends over is another indicator. Persistent bad breath alongside cold symptoms can also signal a sinus infection in kids, though it can have other explanations like poor brushing habits or a sore throat. As with adults, the duration and progression of symptoms matters more than any single sign.
Acute vs. Chronic Sinusitis
An acute sinus infection lasts less than four weeks and is the type most people experience, often triggered by a cold. Chronic sinusitis is a different condition defined by at least two of the four cardinal symptoms (facial pain, reduced smell, nasal drainage, nasal obstruction) persisting for 12 consecutive weeks or longer. Chronic sinusitis doesn’t always involve an active infection. It can stem from ongoing inflammation, nasal polyps, or structural issues in the sinuses.
If you find yourself getting sinus infections multiple times a year, or if your congestion and facial pressure never fully resolve between episodes, that pattern suggests chronic sinusitis rather than repeated acute infections.
Signs That Need Immediate Attention
Sinus infections rarely become dangerous, but the sinuses sit close to the eyes and brain, so infections can occasionally spread. Seek immediate medical care if you notice pain, swelling, or redness around the eyes, double vision or other changes in your vision, a high fever that isn’t responding to treatment, or confusion. These symptoms suggest the infection may be extending beyond the sinuses and requires urgent evaluation. Vision changes in particular warrant a same-day visit, as an infection pressing on the eye socket can progress quickly.