Most sinus infections last 7 to 10 days. The vast majority are caused by viruses, and symptoms typically peak around days three through five before gradually improving on their own. Bacterial sinus infections can stretch longer, but even those usually clear within two to three weeks, often without antibiotics.
Viral Sinus Infections: 7 to 10 Days
About 90% of sinus infections start with a common cold or other viral illness. Congestion, facial pressure, thick nasal discharge, and a dull headache set in as your sinuses become inflamed and swollen. You’ll generally feel the worst during the first week, with noticeable improvement toward the end of the 7-to-10-day window. No antibiotic will shorten this timeline, because antibiotics don’t work on viruses.
Even after the infection itself clears, some symptoms can linger. A residual cough or post-nasal drip often hangs around for three to eight weeks after the main illness resolves. This is common and doesn’t necessarily mean the infection is still active. It’s your irritated airways slowly calming down.
When a Bacterial Infection Takes Over
A smaller number of sinus infections become bacterial, usually as a secondary complication of the original viral illness. Three patterns signal that bacteria may be involved:
- Persistent symptoms: Congestion, nasal discharge, or daytime cough lasting more than 10 days with no improvement at all.
- Severe onset: A fever of 102.2°F (39°C) or higher along with thick, discolored nasal discharge lasting at least 3 to 4 consecutive days from the start of the illness.
- Double worsening: You start feeling better after 5 to 6 days, then suddenly get worse again with new fevers, increased nasal discharge, or worsening headache.
That “double worsening” pattern is particularly useful to watch for. It feels like you’re recovering from a normal cold, then around day five or six, symptoms flare back up. That second wave is a strong indicator that bacteria have moved into the inflamed sinuses.
How Long Bacterial Sinus Infections Last
Bacterial sinus infections typically resolve within two to three weeks. What surprises many people is that most clear on their own. In a large analysis of over 3,000 patients with acute sinus infections, nearly half improved within one week, and two-thirds improved within two weeks, regardless of whether they received antibiotics. A separate analysis found that 80% of patients with bacterial sinus infections improved within two weeks without antibiotic treatment.
This is why many providers take a “watchful waiting” approach, especially if your symptoms are uncomfortable but not severe. If symptoms persist beyond 10 days without any improvement, or if you have the severe or double-worsening patterns described above, antibiotic treatment becomes more appropriate. When antibiotics are prescribed, you’ll typically start feeling better within a few days of starting the course.
Sinus Infections in Children
Kids get diagnosed using the same basic patterns as adults: symptoms persisting more than 10 days without improvement, a worsening course after initial improvement, or severe onset with high fever and thick nasal discharge for at least three consecutive days. The key difference is that children are less likely to report facial pain or headache. Instead, a lingering daytime cough and persistent runny nose (of any color) are the primary clues. Nasal discharge doesn’t need to be green or yellow to indicate a bacterial infection in children.
Chronic Sinusitis: 12 Weeks or More
If sinus symptoms last 12 weeks or longer, the condition is classified as chronic sinusitis. This is a different problem from a single infection that won’t go away. Chronic sinusitis involves ongoing inflammation of the sinus lining, sometimes driven by allergies, nasal polyps, or structural issues rather than an active infection. The symptoms overlap with acute sinusitis (congestion, facial pressure, reduced sense of smell, post-nasal drip), but they’re lower-grade and persistent rather than sudden and intense.
Chronic sinusitis affects roughly 10 to 15% of the population and typically requires a different treatment strategy than a standard sinus infection. Management often focuses on reducing inflammation rather than fighting bacteria.
Signs That Need Prompt Attention
Most sinus infections are genuinely harmless, but the sinuses sit close to the eyes and brain, which means complications, while rare, can be serious. Get medical attention right away if you notice pain, swelling, or redness around your eyes, double vision or other vision changes, a high fever that won’t break, or confusion. These symptoms can indicate the infection has spread beyond the sinuses.
Outside of those emergencies, it’s worth contacting a provider if your symptoms last more than a week without any improvement, if they worsen after initially getting better, or if you deal with repeated sinus infections throughout the year. Recurrent infections (four or more per year) sometimes point to an underlying issue worth investigating.