The biggest clue that you have a sinus infection rather than a lingering cold is persistent facial pressure or pain combined with thick, discolored nasal discharge. If your symptoms haven’t improved after 10 days, or they seemed to get better and then got worse again, you’re likely dealing with a bacterial sinus infection rather than a simple viral cold.
The Core Symptoms of a Sinus Infection
Sinus infections cause a distinct combination of symptoms that, taken together, paint a clear picture. The hallmark is facial pressure and pain, particularly around your eyes, nose bridge, cheekbones, forehead, and temples. This pressure often gets worse when you bend over or move your head around. It can also radiate to your scalp, upper jaw, and teeth, which catches many people off guard.
The other key symptom is thick yellow or green nasal discharge. You may also notice this draining down the back of your throat, often with a foul taste or smell. If bad breath has you reaching for mints more than usual, that post-nasal drip is a likely culprit. Many people also experience a reduced or lost sense of smell, general congestion, and a feeling of fullness in the face that goes beyond typical stuffiness.
How It Differs From a Cold
Colds and sinus infections overlap heavily in their early days, which is why timing matters more than any single symptom. Colds typically improve on their own within 7 to 10 days. If you start feeling worse after 10 to 14 days instead of better, that’s usually the point where a cold has turned into a bacterial sinus infection.
There’s also a pattern called “double worsening.” Your symptoms improve after about 4 to 7 days, making you think you’re recovering, then they come back stronger. That rebound is a strong signal of bacterial infection.
A few other differences help separate the two. Clear discharge is more typical of a cold, while yellow or green discharge leans toward infection. Fever is actually more common with colds than sinus infections, since viruses are more likely to spike your temperature. It takes a severe sinus infection to cause a fever. When a sinus infection does produce a fever of 102°F or higher alongside facial pain and nasal discharge lasting 3 to 4 days, that combination points strongly to a bacterial cause that needs treatment.
How It Differs From Allergies
Allergies and sinus infections can both cause congestion and a runny nose, but itchiness is the dividing line. Seasonal allergies make your eyes itchy, your nose drippy, and the back of your throat scratchy. You’ll find yourself sneezing frequently and rubbing the corners of your eyes. Sinus infections don’t feel itchy. Instead, they bring facial pain, pressure, and that thick discolored discharge.
Allergy discharge tends to be clear and watery. If you’re producing yellow or green mucus, that points toward something more than an allergic reaction. Loss of smell is also more commonly associated with sinusitis than with allergies alone.
Mucus Color Isn’t the Whole Story
Yellow or green mucus gets a lot of attention as a sign of infection, but it’s not as reliable as people think. You can’t tell from mucus color alone whether an infection is viral or bacterial. Your body produces discolored mucus as part of the normal immune response, even during a plain cold. What matters more is how long you’ve been sick, what your overall symptoms are, and whether you’re getting better or worse. A few days of green mucus during a cold that’s clearly resolving is different from persistent discolored discharge paired with worsening facial pain.
Symptoms You Might Not Expect
Upper tooth pain is one of the most surprising symptoms of a sinus infection. The largest sinuses sit directly above your upper back teeth, and the roots of those teeth are so close to the sinus cavity that they sometimes extend into it. When inflammation builds up in those sinuses, it can create pain that feels exactly like a toothache. If your upper molars ache and you also have nasal congestion and facial pressure, the sinuses are a more likely explanation than a dental problem.
Bad breath is another symptom people don’t always connect to their sinuses. Infected mucus draining down the back of your throat carries bacteria and has a distinct foul smell. Headaches, fatigue, and ear pressure round out the list of secondary symptoms that often accompany a sinus infection but get blamed on other causes.
When a Sinus Infection Becomes Chronic
Most sinus infections resolve within a few weeks, either on their own or with treatment. But if your symptoms persist for 12 weeks or more, you’ve crossed into chronic sinusitis. This is a different condition that requires a different approach. Chronic sinusitis involves ongoing inflammation rather than a single infection, and it often needs a more thorough evaluation to identify what’s keeping the cycle going, whether that’s nasal polyps, structural issues, or persistent low-grade inflammation.
What Happens at a Doctor’s Visit
Most sinus infections are diagnosed based on your symptoms and their timeline. Your doctor will ask how long you’ve been sick, whether symptoms improved and then worsened, and about the character of your discharge and pain. For straightforward cases, that conversation is usually enough.
If your symptoms are recurring, unusually severe, or haven’t responded to treatment, your doctor may look inside your nasal passages with a thin, flexible scope. Before inserting it, they’ll spray a decongestant and numbing medication into your nose to keep you comfortable. The scope lets them see swelling, discharge, or structural problems that aren’t visible from outside. In some cases, a CT scan provides additional detail about the sinus cavities, but imaging is typically reserved for chronic or complicated cases rather than a first-time infection.