A sinus infection produces cloudy or colored nasal drainage combined with a stuffy nose, facial pressure, or both, and these symptoms either persist for 10 days or longer without improving, or get noticeably worse after initially getting better. That pattern of not improving or worsening is the single most reliable way to distinguish a sinus infection from a regular cold, which typically clears up on its own within 7 to 10 days.
The Core Symptoms
The 2025 clinical practice guideline from the American Academy of Otolaryngology defines acute sinusitis as up to four weeks of cloudy or colored (not clear) nasal drainage plus at least one of the following: a stuffy, congested, or blocked nose, or pain, pressure, and fullness in the face, head, or around the eyes. You need both the discharge and at least one of those accompanying symptoms to consider it a true sinus infection rather than something else.
Other common signs include pain over the cheeks that radiates toward your forehead or upper teeth, reduced sense of smell, and postnasal drip that triggers a cough, especially at night. Bending forward or straining often makes the facial pressure worse, which is a hallmark of sinus involvement. You may also notice fatigue and a general feeling of being unwell that lingers well past the point where a cold should have resolved.
Cold, Allergies, or Sinus Infection?
Most sinus symptoms are caused by viral infections or allergies, not bacterial infections. A typical cold follows a predictable arc: symptoms peak around days three to five, then gradually improve. If you’re still sick on day 10 with no improvement at all, or if you started feeling better around days four to seven and then got worse again, the infection has likely become bacterial. That second pattern, where you seem to turn a corner only to slide backward, is called “double sickening,” and it’s one of the clearest signals that your body isn’t fighting this off alone.
The CDC uses three scenarios to flag a probable bacterial sinus infection: symptoms lasting 10 or more days without improvement, a fever of 102°F or higher with facial pain and nasal discharge persisting for three to four consecutive days, or that double sickening pattern within the first 10 days of illness. If none of these apply, you’re most likely dealing with a virus that will resolve on its own.
Allergies can mimic some of these symptoms, particularly congestion and drainage. But allergies tend to produce clear, thin mucus, itchy eyes, and sneezing, and they follow seasonal or environmental triggers rather than a cold-like illness timeline.
Why Mucus Color Isn’t Reliable
Green or yellow mucus is one of the most commonly cited “signs” of a bacterial infection, but it’s not actually a useful indicator. Your body produces colored mucus whenever white blood cells respond to any irritant, viral or bacterial. The enzymes these cells release contain iron, which tints the discharge green. Mucus also darkens when it sits still, like while you sleep, which is why mornings often bring the thickest, most alarming-looking discharge regardless of what’s causing it.
Seasonal allergies can produce thick yellow or green mucus with no infection at all. So can a standard cold virus. The timeline and trajectory of your symptoms matter far more than what’s on the tissue.
How to Check at Home
You can gently press on a few areas of your face to get a sense of sinus involvement. The key spots are just above the inner corner of each eye (where the frontal sinuses sit), the cheekbones below the eyes, and the bridge of the nose. If pressing on these areas produces a distinct, localized tenderness or pain, your sinuses are likely inflamed. That said, facial tenderness alone doesn’t confirm a bacterial infection. It tells you the sinuses are involved but not necessarily why.
What matters more than any single physical check is tracking your symptoms over several days. Keep a rough mental log: Are things getting better, staying flat, or getting worse? The trajectory is the most useful diagnostic tool you have at home.
Signs in Children
Kids don’t always describe sinus pressure or facial pain the way adults do. In children, a sinus infection often looks like a cold that simply won’t quit: nasal discharge and a daytime cough lasting more than 10 days without improvement. A fever combined with thick yellow nasal discharge that persists for three or four days is another strong indicator.
Some signs are easier to spot from the outside. Swelling and dark circles around the eyes, particularly in the morning, point toward sinus involvement. Persistent bad breath that accompanies cold symptoms can also be a clue, though it’s worth noting that bad breath in kids has plenty of other explanations, from a sore throat to inconsistent tooth brushing. A severe headache behind or around the eyes that worsens when bending over is more specific and worth taking seriously.
When It Becomes Chronic
If your sinus symptoms drag on for 12 weeks or more, the condition is classified as chronic sinusitis. Unlike acute sinusitis, which typically resolves within 10 days, chronic sinusitis involves persistent inflammation that may include recurring flare-ups layered on top of a baseline of nasal blockage, drainage, and low-grade facial discomfort. Some people with chronic sinusitis never feel fully clear between episodes.
Recurrent acute sinusitis is a separate category. This means you get multiple distinct sinus infections throughout the year but return to a healthy, symptom-free baseline between them. The distinction matters because the two conditions have different underlying causes and are managed differently.
Symptoms That Need Immediate Attention
Sinus infections rarely become dangerous, but the sinuses sit close to the eyes and brain, and infection can occasionally spread. Seek care right away if you notice swelling, redness, or pain around your eyes, double vision or other changes in your eyesight, a high fever that doesn’t respond to typical treatment, a stiff neck, or confusion. These symptoms suggest the infection may be extending beyond the sinuses and require urgent evaluation.