A sinus infection typically announces itself with facial pain or pressure, thick discolored nasal discharge, and congestion that lasts longer than 10 days or gets worse after initially improving. Those are the hallmarks that separate a sinus infection from the ordinary cold it often follows. But the picture isn’t always obvious, and several conditions can look similar, so knowing what to pay attention to and when matters.
The Core Symptoms
Sinus infections cause a specific cluster of symptoms that tend to show up together. The most reliable signs are a swollen, painful feeling around your forehead, eyes, and cheeks; a stuffy nose with thick, colored mucus; a bad-tasting postnasal drip; bad breath; sore throat; cough; and fatigue. You may also run a low-grade fever, though high fevers are less common with a typical sinus infection.
The pain tends to concentrate in predictable spots depending on which sinuses are affected. Pressure across the forehead, aching between or behind the eyes, or tenderness in the cheeks just below the eyes are all common patterns. Bending forward often makes the pain worse because it increases pressure in the inflamed sinuses.
How It Differs From a Cold or Allergies
A cold develops over several days and should clear up within about a week. It can include a sore throat, mild fever, body aches, and a runny nose. A sinus infection often starts as a cold but then lingers. If your stuffy nose and cough are still going strong after one to two weeks, a sinus infection becomes much more likely.
Allergies, on the other hand, begin shortly after you’re exposed to a trigger (pollen, dust, pet dander) and last as long as the exposure does. The telltale difference is itchiness: watery, itchy eyes and frequent sneezing point toward allergies rather than infection. Allergies also don’t cause fever or the thick, discolored discharge that sinus infections produce.
The 10-Day Rule and “Double Sickening”
Most sinus infections start with a virus, and most viral sinus infections resolve on their own. The question people really want answered is whether their infection has turned bacterial, because that’s when antibiotics may actually help. There are three patterns that suggest a bacterial infection:
- Symptoms lasting 10 days with no improvement. Not 10 days total, but 10 days without getting better at all. A cold that’s slowly fading is still a cold.
- Severe onset. A fever of 102°F or higher along with facial pain and discolored nasal discharge lasting three to four consecutive days points toward bacteria from the start.
- Double sickening. You start to feel better after four to seven days, then your symptoms come roaring back. This worsening after initial improvement is one of the most reliable signs of a bacterial infection settling in.
If none of these patterns apply, you’re likely dealing with a viral infection that will run its course. Antibiotics won’t help a viral sinus infection.
The Mucus Color Myth
Green or yellow mucus is widely believed to mean a bacterial infection, but this is a myth, one that even some doctors fall for. Both viral and bacterial infections cause the same changes to mucus color. The greenish tint comes from enzymes released by your white blood cells as they fight infection, regardless of whether the invader is a virus or bacteria. Mucus color alone is not a reason to take antibiotics.
What does matter about your discharge is where it shows up and how long it lasts. Thick, discolored discharge from one side of your nose (rather than both) is more suggestive of a bacterial sinus infection than symmetric congestion.
Signs in Children
Kids get sinus infections too, but their symptoms can look a bit different. In children, the key signs include cold symptoms (runny nose, daytime cough, or both) lasting more than 10 days without improving, thick yellow discharge paired with a fever lasting three to four days, swelling and dark circles around the eyes (especially in the morning), and a severe headache behind the eyes that worsens with bending over.
Persistent bad breath alongside cold symptoms is another clue in children, though it can also come from a sore throat or poor brushing habits. Young kids generally can’t describe sinus pressure the way adults do, so lasting congestion and a cough that won’t quit are often the most visible indicators.
Acute vs. Chronic Sinusitis
Acute sinusitis refers to symptoms lasting less than four weeks. This is the common type that follows a cold. Chronic sinusitis means symptoms have persisted for three months or longer, and it’s a different situation entirely. Chronic sinusitis is often driven by ongoing inflammation, nasal polyps, or structural issues rather than a single bacterial infection, and it typically requires a different treatment approach.
If your sinus symptoms keep coming back several times a year or never fully go away, that pattern matters more than any single episode.
Symptoms That Need Immediate Attention
Most sinus infections are uncomfortable but not dangerous. A small number can spread to nearby structures, and these warning signs mean you should get medical care right away: pain, swelling, or redness around the eyes; a high fever; confusion; double vision or other changes in your sight; or a stiff neck. These can indicate the infection has moved beyond the sinuses into the eye socket or toward the brain, which requires urgent treatment.