If you’ve ever had a sinus infection, you know how uncomfortable—and persistent—they can be.
You can’t breathe normally due to nasal congestion, postnasal drip interferes with sleep, and sinus pain makes your face ache.
Add in possible nasal discharge, headache, cough, fatigue, and fever, and no wonder you just want it to go away.
Unfortunately, sinus infections may last longer than you think: Acute sinusitis lasts up to four weeks, while chronic sinusitis lasts at least three months.
Although these infections don’t require treatment, if you’re uncomfortable, over-the-counter remedies such as decongestants and nasal saline irrigation, as well as lifestyle changes like increased fluid intake, may provide some symptom relief.
On the other hand, in most cases, antibiotics don’t help treat a sinus infection and may cause more harm.
However, antibiotics can be appropriate for some sinus infections. It all comes down to whether a virus or bacteria is causing the infection.
To help clear up the confusion about antibiotics for sinus infections, in this article, I’ll explain the differences between viral and bacterial sinus infections.
I will also discuss when to use antibiotics to treat a sinus infection and what types of sinus infections antibiotics treat.
Viral vs Bacterial Sinus Infections
Most sinus infections are caused by viruses (such as the common cold) that create inflammation in the sinuses, leading to blockage that can make it hard to breathe, nasal secretions, postnasal drip, and other discomfort like facial pain around your eyes, cheeks, nose, or forehead.
Knowing this—and that antibiotics don’t work on viral infections—most healthcare providers first recommend treatments to relieve the symptoms of a sinus infection while you wait for it to resolve.
These may include:
- A nasal irrigation system such as a neti pot
- Nasal sprays with corticosteroids
- Over-the-counter decongestants such as pseudoephedrine
- Antihistamines (if your symptoms may be due to underlying allergies)
- Pain relievers like acetaminophen (Tylenol) or ibuprofen (Advil, Motrin) to ease discomfort from swelling, fever, or sore throat
In rare cases, viral sinus infections can lead to bacterial growth in the nasal passages.
There’s no way to know for sure if you have a bacterial sinus infection without testing a mucus sample.
But even without a sample, two signs typically indicate a bacterial infection and may prompt your provider to prescribe antibiotics:
- A sinus infection that lasts for more than 10 days
- Symptoms of the infection resolve, then back worse a couple days later
Some people think yellow or green mucus may be a sign of a bacterial sinus infection, but colored mucus can occur with viral infections and does not necessarily mean you have a bacterial infection.
If you do have bacterial sinusitis (also called bacterial rhinosinusitis), it should respond to antibiotics within a few days.
If your primary care provider suspects your infection is bacterial and your antibiotic medication isn’t helping, contact them for additional medical advice.
When to Use Antibiotics to Treat a Sinus Infection
Antibiotics only work against bacterial infections, so the best time to use them for a sinus infection is when you and your doctor suspect bacteria caused the infection.
Otherwise, you may be at risk for unwanted side effects or even antibiotic resistance.
When this happens, bacteria outsmart the medications designed to kill them, and the antibiotics no longer work when you need them.
That said, it can be hard to know whether a sinus infection is viral or bacterial.
Some scenarios, such as an infection that persists longer than 10 days or an infection that goes away and then returns, may indicate a bacterial infection and prompt a provider to prescribe antibiotics.
In some cases, a healthcare provider may also treat a sinus infection with antibiotics as a precaution to prevent complications in people with compromised immune systems that can’t easily fight off infections.
If your doctor prescribes antibiotic treatment, follow their instructions.
Take the antibiotics at the same time every day. If you miss a dose, take it when you remember or, if it’s close to your next dose, wait until then and take one dose.
Do not double up on antibiotics doses.
If you experience unwanted side effects of antibiotics, your sinus infection isn’t improving, or you develop new symptoms, contact your healthcare provider, who can help you figure out what’s going on.
While sinus infections usually don’t cause major medical problems, they can have severe symptoms and other complications.
In rare cases, an untreated sinus infection can lead to meningitis, or inflammation of the membranes that surround the brain and spinal cords.
Rarely, an untreated sinus infection can also cause an infection of the brain.
Some people also experience allergic reactions to antibiotics, so tell your doctor if this has ever happened to you so they can prescribe another type of antibiotic treatment.
Do Antibiotics Treat Sinus Infections?
Antibiotics are a type of medication that stops bacteria from growing and, as a result, improves symptoms of an infection.
Healthcare providers only prescribe antibiotics for sinus infections that they believe are bacterial.
Antibiotics don’t work on viral or fungal infections, and taking antibiotics when you don’t need them can cause unnecessary side effects such as diarrhea, nausea, and stomach pain.
Plus, taking antibiotics too often can create antibiotic resistance.
The most common antibiotics prescribed for sinus infections are penicillin-class antibiotics such as amoxicillin (Amoxil) or amoxicillin-clavulanate (Augmentin).
If you have a penicillin allergy, a common alternative is doxycycline.
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K Health articles are all written and reviewed by MDs, PhDs, NPs, or PharmDs and are for informational purposes only. This information does not constitute and should not be relied on for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment.
K Health has strict sourcing guidelines and relies on peer-reviewed studies, academic research institutions, and medical associations. We avoid using tertiary references.
Acute Sinusitis. (2021).
Antibiotics and Topical Nasal Steroid for Treatment of Acute Maxillary Sinusitis. (2007).