Most sinus infections clear up within 7 to 10 days. The vast majority are caused by viruses, and many of those resolve even faster, in 3 to 5 days. If your symptoms persist beyond 10 days or get noticeably worse after an initial improvement around day 5 or 6, you’re likely dealing with a bacterial infection that may need antibiotics.
Viral vs. Bacterial: Two Different Timelines
About 90% of sinus infections start with a virus, usually the same one that gave you a cold. Viral sinusitis typically resolves within 3 to 5 days, though lingering congestion can stretch closer to a week or 10 days. You won’t need antibiotics for this type, and they wouldn’t help even if you took them.
Bacterial sinus infections are less common and last longer. The hallmark is symptoms that hang around for more than 10 days without any improvement. Another pattern to watch for: you start feeling better after a few days, then around day 5 or 6 your symptoms come back worse than before. That “double worsening” strongly suggests bacteria have moved in on top of the original viral infection.
How Doctors Decide It’s Bacterial
There’s no quick test to tell viral from bacterial sinusitis in most cases. Instead, clinicians rely on three patterns to decide whether antibiotics are warranted:
- Persistent symptoms: At least 10 days of congestion, facial pressure, or nasal discharge with no sign of improvement.
- Double worsening: A typical cold that seems to improve, then worsens again after 5 to 6 days with renewed sinus symptoms.
- Severe onset: A fever of 102°F or higher lasting at least 3 to 4 days, along with thick discolored nasal discharge or significant facial pain.
If none of those criteria apply, the infection is almost certainly viral, and the best approach is managing symptoms while your immune system handles it.
What to Expect With Antibiotics
If you do get a prescription for a bacterial sinus infection, you should notice improvement within 3 to 5 days of starting the medication. Older adults and people with other health conditions sometimes take a bit longer, but even in those cases, some degree of symptom relief should be apparent within 5 days. If nothing has changed by then, your doctor may need to reassess or switch to a different antibiotic.
Full resolution can take longer than the initial improvement. Even after you start feeling noticeably better, some residual congestion or mild pressure may linger for a few more days before completely clearing.
When a Sinus Infection Drags On for Weeks
Doctors classify sinusitis by how long it lasts. Acute sinusitis covers anything under 4 weeks. Subacute sinusitis runs from 4 to 12 weeks. Chronic sinusitis means symptoms have persisted for more than 12 weeks. These aren’t just labels; they point to different underlying problems and different treatment approaches.
Chronic sinusitis is rarely just an infection that never went away. It’s typically driven by ongoing inflammation from allergies, nasal polyps (small growths on the sinus lining), or structural problems inside the nose. People who smoke or are regularly exposed to secondhand smoke also face a higher risk. A weakened immune system, whether from a medical condition or medications, can make it harder for the body to resolve sinus inflammation on its own.
Factors That Slow Recovery
Several things can extend how long your sinus infection takes to clear. Seasonal allergies keep the sinus lining inflamed, making it harder for mucus to drain normally. Smoking irritates the tissue and impairs the tiny hair-like structures that sweep mucus out of your sinuses. Even a recent cold can leave your sinuses vulnerable to a second infection before they’ve fully recovered from the first one.
Structural issues play a role too. A deviated septum or nasal polyps can physically block the drainage pathways your sinuses depend on. When mucus can’t flow out, bacteria have a warm, moist environment to thrive in, which is why some people get sinus infections repeatedly while others rarely do.
Symptom Relief While You Wait It Out
Since most sinus infections are viral and resolve on their own, the main goal during that 7 to 10 day window is comfort. Over-the-counter pain relievers can help with facial pressure and headaches. Decongestants, either oral or nasal sprays, can temporarily open up blocked passages, though nasal spray decongestants shouldn’t be used for more than 3 days in a row because they can cause rebound congestion that makes things worse.
Saline nasal rinses are widely recommended, though the research supporting them for acute infections is actually thin. Controlled trials have not consistently shown that saline irrigation shortens the duration of a sinus infection compared to simply waiting it out. That said, many people find them soothing, and they carry virtually no risk. Breathing in steam from a hot shower or a bowl of hot water can also temporarily loosen congestion. Staying well hydrated helps keep mucus thinner and easier to clear.
The bottom line for most people: if your symptoms are steadily improving, even slowly, you’re on track. A sinus infection that’s getting better on its own, even if it’s taking a full week or more, is following the normal course. It’s the infection that stalls out, worsens after initial improvement, or comes with a high fever and severe pain that warrants a closer look.