A sinus infection feels like a cold that won’t quit, with pressure and pain centered in your face that builds rather than fades over time. The key distinction: most colds improve within 7 to 10 days, while a sinus infection either lingers beyond that window, gets worse after initially improving, or hits hard with severe facial pain and high fever from the start. Knowing which pattern your symptoms follow helps you figure out whether you’re dealing with simple congestion or something that needs medical attention.
The Core Symptoms
Sinus infections and common colds share many of the same symptoms, which is exactly why they’re so hard to tell apart in the first few days. Both cause nasal congestion, runny nose, and a general feeling of being unwell. But sinus infections add a layer of facial pressure and pain that a typical cold doesn’t produce, or produces only mildly.
The hallmark symptoms of a sinus infection include thick nasal discharge (often discolored), a feeling of fullness or pressure in your face, reduced sense of smell, and congestion that makes it hard to breathe through your nose. Many people also experience postnasal drip, where mucus runs down the back of your throat, triggering a cough that tends to worsen at night. Fatigue, mild fever, and bad breath round out the picture.
Where It Hurts Tells You Which Sinuses Are Affected
You have four pairs of sinus cavities in your skull, and the location of your pain maps directly to which ones are inflamed. Pain across your forehead points to the frontal sinuses. Aching in your cheekbones or upper teeth signals the maxillary sinuses, the largest pair, which sit just above the roots of your upper back teeth. Pain at the bridge of your nose involves the ethmoid sinuses, and a deeper ache behind your eyes or in your ears suggests the sphenoid sinuses.
Upper tooth pain in particular catches people off guard. The roots of your upper back teeth sit very close to, or even extend into, the maxillary sinus cavity. When those sinuses swell, the inflammation presses directly on nearby tooth roots. This referred pain is common enough that people sometimes visit a dentist before realizing the real problem is in their sinuses.
The Timing That Matters Most
Timing is the single most useful tool for telling a sinus infection apart from a cold. A standard cold follows a predictable arc: symptoms peak around days 3 to 5, then gradually improve. If your symptoms haven’t started getting better by day 10, that’s a strong signal that a sinus infection has developed.
There’s also a pattern called “double sickening.” You start feeling better after a few days, then your symptoms return and get noticeably worse. This rebound often means a bacterial infection has taken hold on top of the original viral illness. A fever lasting more than 3 to 4 days is another red flag, since cold-related fevers typically break much sooner.
Severe symptoms appearing right at the start, like intense facial pain or a high fever, can also indicate a bacterial sinus infection rather than a slow progression from a cold. In short, the three patterns to watch for are: symptoms lasting beyond 10 days without improvement, symptoms that worsen after initially getting better, and symptoms that start severe.
Green Mucus Doesn’t Mean What You Think
One of the most persistent beliefs about sinus infections is that green or yellow mucus means you have a bacterial infection and need antibiotics. This is a myth, and according to the Mayo Clinic, even some healthcare providers get this wrong. Both viral and bacterial infections cause the same changes in mucus color and thickness. Viruses cause the vast majority of upper respiratory infections, and antibiotics do nothing against them regardless of what color your mucus is.
There is one subtle difference worth knowing. With a viral infection, mucus typically starts clear and turns thicker and more colorful several days in, as your immune system ramps up its response. With a bacterial infection, thick, discolored mucus more often shows up right at the beginning. But this distinction alone isn’t reliable enough to diagnose anything. Duration and symptom patterns matter far more than what’s on your tissue.
Acute vs. Chronic Sinus Infections
Most sinus infections are acute, meaning they develop quickly and resolve within a few weeks, often without antibiotics. Acute sinusitis typically follows a cold, an allergy flare, or exposure to an irritant, and even bacterial cases frequently clear on their own with supportive care like saline rinses, decongestants, and pain relievers.
Chronic sinusitis is a different condition. If your symptoms persist for 12 weeks or more, you’ve crossed the threshold from acute to chronic. Chronic sinusitis isn’t just a long infection. It involves ongoing inflammation in the sinus lining that can be driven by allergies, nasal polyps, a deviated septum, or immune system issues. The symptoms overlap with acute sinusitis (congestion, facial pressure, reduced smell, postnasal drip) but tend to be less intense and more constant. People with chronic sinusitis often describe it less as “being sick” and more as a persistent dullness in their face that never fully lifts.
Symptoms That Need Immediate Attention
Sinus infections rarely become dangerous, but the sinuses sit close to your eyes and brain, and in uncommon cases, infection can spread to those areas. Seek emergency care if you notice swelling or redness around your eye, changes in vision (double vision or reduced sight), a bulging eye, severe headache that doesn’t respond to pain medication, stiff neck, high fever with confusion or changes in alertness, or focal neurological symptoms like weakness on one side of your body. These signs suggest the infection may be affecting the orbit of the eye or the lining of the brain and require urgent evaluation.