How Long Does a Sinus Infection Last Without Antibiotics?

Most sinus infections resolve on their own in 7 to 10 days. The large majority — commonly cited as around 90–98% in adults — are viral, which means antibiotics have no effect on them at all.

The typical timeline

The 10-day rule

Doctors use a fairly consistent set of criteria to decide whether a sinus infection has become bacterial and worth treating:

1. Symptoms lasting more than 10 days with no improvement at all, or
2. Severe symptoms from the start — fever above 102°F with thick discharge and facial pain for three or more consecutive days, or
3. Double worsening — you were getting better, then got clearly worse again after day five or six

That third pattern is the strongest signal. Steady improvement, even slow improvement, points to a virus running its course.

Why green mucus does not mean antibiotics

This is the most persistent myth in this area. The green or yellow colour comes from an enzyme released by white blood cells fighting the infection. It appears in ordinary viral colds, usually around day three to five. Colour alone tells you nothing about whether bacteria are involved.

Our article on why antibiotics do not work on viral infections explains the mechanism.

What actually helps

Saline nasal rinse — the most effective option

A high-volume saline rinse using a neti pot or squeeze bottle physically flushes mucus and inflammatory material out of the nasal passages. Evidence supports it, and it works better than saline spray.

Safety note: use only distilled, sterile, or previously boiled and cooled water. Never tap water. This matters — rare but serious infections have been linked to tap water rinses.

Steroid nasal spray

Fluticasone or triamcinolone reduce swelling in the nasal passages and help drainage. Available over the counter. These take several days to reach full effect, so start early and use consistently rather than as needed.

Decongestants, briefly

Pseudoephedrine (behind the pharmacy counter) can relieve pressure. Do not use decongestant nasal sprays like oxymetazoline for more than three days — longer use causes rebound congestion that is worse than the original problem.

Note that oral phenylephrine, the ingredient in many front-of-shelf products, has been found ineffective. See what the FDA ruling on phenylephrine changed.

Pain relief and steam

Ibuprofen helps with facial pain and inflammation. Warm compresses and steam from a shower provide temporary relief.

When it is not actually sinusitis

Facial pressure and headache are frequently attributed to sinuses when the real cause is migraine. If you have light sensitivity or nausea but no thick discharge and no reduced sense of smell, read headache behind the eyes.

To work out whether your cold has actually crossed over, see sinus infection versus cold.

Chronic sinusitis

Symptoms lasting more than 12 weeks are classified as chronic and managed differently — usually with steroid sprays, rinses, and investigation for underlying causes such as nasal polyps, allergies, or structural problems. This needs a specialist referral, not repeated antibiotic courses.

Seek urgent care for

Swelling or redness around the eye, vision changes or double vision, severe headache with a stiff neck, confusion, or high fever with severe forehead pain. These are uncommon but serious complications.

Related reading

• Why Antibiotics Do Not Work on Viral Infections
• Phenylephrine Does Not Work: What the FDA Ruling Changed
• Headache Behind the Eyes: Sinus, Migraine, or Something Else

Sources

• Influenza (Flu) — Centers for Disease Control and Prevention
• MedlinePlus — U.S. National Library of Medicine
• Over-the-Counter Medicines — MedlinePlus