A sinus infection, also called sinusitis, is inflammation or swelling of the tissue lining your sinuses. These are the hollow spaces behind your forehead, cheeks, nose, and eyes. When they become blocked and fill with fluid, germs can grow and cause an infection. Most sinus infections start as a common cold and clear up within one to two weeks, but some turn bacterial and linger much longer.
What Causes a Sinus Infection
Most sinus infections begin with a virus, the same kind that causes the common cold. Your sinuses swell, mucus can’t drain properly, and pressure builds. In most people, this resolves on its own. But in roughly 0.5% to 2% of cases, a bacterial infection develops on top of the viral one. When researchers have sampled fluid directly from the sinuses of people with suspected bacterial sinusitis, about half showed bacterial growth.
Several underlying conditions make sinus infections more likely or harder to shake. Allergies and asthma top the list because they keep your airways inflamed and your sinus tissue swollen. Nasal polyps (small growths inside the nose) can physically block drainage. Tooth infections can spread into the sinuses. A weakened immune system also leaves you more vulnerable.
Common Symptoms
The hallmark symptoms of a sinus infection include a stuffy or runny nose, facial pain or pressure (especially around the cheeks, forehead, and eyes), headache, and mucus dripping down the back of your throat. You may also notice bad breath, a sore throat from that post-nasal drip, a cough that worsens at night, ear pressure, aching teeth, a reduced sense of smell, and general fatigue. Fever is possible but not always present.
The pressure and pain tend to get worse when you bend forward. That’s because the position shifts fluid inside the blocked sinuses, increasing the sensation of fullness.
Sinus Infection vs. a Cold
A cold and a sinus infection share many symptoms, which makes them easy to confuse. The key differences are timing and specific symptoms. Colds generally improve on their own within 7 to 10 days. If you start feeling worse after 10 to 14 days instead of better, that’s typically the point where a cold has progressed into a bacterial sinus infection.
Two symptoms help distinguish the two: facial pressure and discolored nasal drainage. Thick yellow or green mucus, combined with pain or pressure concentrated around your face, suggests the infection has moved beyond a simple cold. A cold usually produces clear or slightly whitish mucus and causes more generalized congestion without that localized facial pain.
Acute vs. Chronic Sinusitis
Doctors classify sinus infections by how long they last. Acute sinusitis is the most common form and usually resolves within one to two weeks, though it can take up to several weeks at the outer edge. You can get acute sinusitis multiple times a year, but each episode eventually clears.
If your symptoms persist for more than three months, it’s considered chronic sinusitis. Chronic cases are less about a single infection and more about ongoing inflammation. They’re strongly linked to allergies, asthma, nasal polyps, or structural issues that prevent your sinuses from draining properly. The symptoms are similar to acute sinusitis but tend to be less intense and more constant, a persistent low-grade misery rather than a sharp illness.
Home Remedies That Help
For most sinus infections, over-the-counter options and home care are the first line of relief. Decongestants work by narrowing blood vessels to reduce the swelling that causes congestion, which helps your sinuses open up and drain. They come in both pill and nasal spray form, but nasal spray decongestants shouldn’t be used for more than three consecutive days, as they can cause rebound congestion.
Saline nasal rinses are one of the most effective things you can do. They flush out thick mucus and help your sinuses drain. You can use a squeeze bottle, bulb syringe, or neti pot. One important safety note: never use plain tap water for a nasal rinse. Tap water can contain low levels of bacteria and amoebas that are harmless when swallowed (stomach acid kills them) but can cause serious, even fatal, infections when introduced into nasal passages. Use only distilled water, sterile water, or tap water that’s been boiled for 3 to 5 minutes and cooled to lukewarm. Previously boiled water should be used within 24 hours.
Other simple measures include staying hydrated, breathing in steam from a hot shower, applying a warm compress to your face, and sleeping with your head slightly elevated to promote drainage.
When Antibiotics Are Needed
Because most sinus infections are viral, antibiotics won’t help in the majority of cases. Antibiotics only work against bacteria. Your doctor will typically consider antibiotics if your symptoms haven’t improved after 10 days, if symptoms are severe (high fever with thick discolored drainage lasting 3 to 4 consecutive days), or if symptoms initially improve and then suddenly worsen.
Taking antibiotics when they aren’t needed contributes to antibiotic resistance and can cause unnecessary side effects. This is one of the most over-prescribed medications in outpatient care, so don’t be surprised if your doctor recommends waiting and managing symptoms rather than prescribing right away.
Warning Signs of Complications
Serious complications from sinus infections are rare, but they do happen. Because your sinuses sit close to your eyes and brain, an untreated bacterial infection can occasionally spread to surrounding tissue. The most concerning complications involve the eye socket. Swelling around the eye, particularly at the inner corner, can signal orbital cellulitis, an infection of the tissue surrounding the eye. Left untreated, this can progress to a collection of pus behind the eye, potentially causing the eye to bulge forward, restricted eye movement, and vision loss.
In the most severe cases, infection can travel along the veins behind the eye into the brain’s blood vessels or spread into the space surrounding the brain. These are medical emergencies.
Seek immediate care if you notice swelling or redness around your eyes, vision changes, a stiff neck, a high fever that won’t break, or severe headache that feels different from typical sinus pressure. Facial swelling and symptoms that keep worsening after two weeks also warrant a prompt medical visit.