Most sinus infections last 7 to 10 days. The vast majority are caused by viruses and clear up on their own within that window, much like a common cold. When symptoms drag past 10 days without improving, the infection may have become bacterial, which can extend the timeline to several weeks and sometimes requires antibiotics.
Viral vs. Bacterial: The 10-Day Rule
Almost all sinus infections start as viral infections, and most follow a predictable arc. You feel congested, your face aches, you have thick nasal discharge, and then things gradually improve over 7 to 10 days. No antibiotics needed, no special intervention.
The 10-day mark is the key dividing line. If your symptoms persist for 10 days with no signs of improvement, the infection is likely bacterial rather than viral. There are two other patterns that also point to a bacterial cause: a high fever (102°F or above) with facial pain and thick, discolored nasal discharge lasting 3 to 4 days, or symptoms that seem to get better after 4 to 7 days only to suddenly worsen again. That “double worsening” pattern is a classic red flag. Most common colds resolve within 5 to 7 days, so getting worse around day 7 instead of better is a signal that bacteria have taken hold.
Even bacterial sinus infections often resolve without antibiotics. In clinical trials, about 66% of patients recovered within 14 days without antibiotic treatment, compared to 80% who took antibiotics. The difference wasn’t statistically significant, which is why many doctors recommend watchful waiting before prescribing anything.
Acute, Subacute, and Chronic Timelines
Sinus infections are classified into three categories based on how long they last:
- Acute sinusitis lasts less than 4 weeks. This covers the typical viral and bacterial infections most people experience. With or without treatment, symptoms resolve within this window for the vast majority of people.
- Subacute sinusitis lasts 4 to 12 weeks. This usually happens when an acute infection doesn’t fully respond to initial treatment. Symptoms are often milder than the acute phase but stubbornly persistent.
- Chronic sinusitis lasts 12 weeks or longer. This is a different condition from a lingering cold. Chronic sinusitis involves ongoing inflammation in the sinuses, often driven by repeated acute infections, structural issues like nasal polyps, or allergies rather than a single active infection.
How Long Sinus Infections Last in Children
Children follow roughly the same timeline as adults, but the early signs look a little different. In younger kids, the main symptom is a runny nose that lasts longer than 7 to 10 days. Older children tend to have symptoms more similar to adults, including facial pressure and thick discharge. The same classification system applies: acute (under 4 weeks), subacute (4 to 12 weeks), and chronic (12 weeks or more). Children who get repeated acute infections that aren’t fully treated are at higher risk of developing chronic sinusitis.
What Helps (and What to Avoid)
During the first 10 days, the goal is symptom relief while the infection runs its course. Saline nasal rinses, steam, staying hydrated, and over-the-counter pain relievers for facial pressure all help make the wait more tolerable.
Nasal decongestant sprays can provide quick relief from congestion, but limit their use to 3 consecutive days. Beyond that, you risk rebound congestion, where the spray itself starts causing the stuffiness it was meant to treat. This can create a frustrating cycle that makes your symptoms feel like they’re lasting far longer than the actual infection.
If your symptoms cross the 10-day threshold without any improvement, or if you experience the double-worsening pattern described above, that’s the point where antibiotics become a reasonable option. A bacterial sinus infection treated with antibiotics typically starts improving within a few days, though you’ll usually take the full course for 5 to 10 days.
Signs Your Infection Needs Urgent Attention
Most sinus infections, even bacterial ones, are uncomfortable but not dangerous. A few warning signs suggest something more serious is happening. Swelling around the eyes (especially in children), a severe headache that doesn’t respond to pain medication, a high fever that won’t break, or vision changes all warrant prompt medical evaluation. These can indicate the infection has spread beyond the sinuses into surrounding structures. Patients with weakened immune systems should be especially alert to rapidly worsening symptoms, as they’re at higher risk for aggressive fungal sinus infections that need immediate treatment.