This post has been updated November, 2022
After my series about antibiotic use a reader asked a question about sinus infections.
“How do I know if I need an antibiotic for a sinus infection?”
If you have a bacterial sinus infection with more than mild symptoms, an antibiotic may relieve symptoms and help you recover sooner.
“How do I, or my doctor, know that I have a bacterial sinus infection?”

Your symptoms may be one of these diagnoses, not bacterial sinusitis
Since the nose and sinuses are directly connected, problems in one part affect the other.
You may have a common cold, medically called acute viral rhinosinusitis. The medical prefix “rhino” refers to the nose, for obvious reasons.
It’s also sometimes called an upper respiratory infection or nasopharyngitis. But the main difference is -it’s caused by a VIRUS, not bacteria. Many viruses cause colds or cold-like illnesses, including SARS-CoV-2, RSV, and influenza.
Allergic rhinitis, commonly just caused “allergies” or hay fever; again, a more correct diagnosis is allergic rhinosinusitis.

Non-sinus problems

The problem may not come from the sinuses. Other areas in the head may cause symptoms that you or your doctor may believe is due to sinusitis. These include
- An abscessed tooth, or other dental problem
- Cellulitis, an infection of the deeper layer of the skin
- Zoster, known by its common name shingles; prior to the onset of the rash, there may be pain alone
- Migraine– the headache of migraine can cause pain in the sinus area
an uncommon sinusitis mimic
Angioedema – You may not be familiar with this, it’s a type of allergic reaction characterized by swelling, mostly in the throat, lips, eyes, and cheeks.
Once a patient called me requesting an antibiotic for a sinus infection. My office nurse wisely scheduled an appointment with me. Rather than a sinus infection, the patient was experiencing angioedema from blood pressure medication. These reactions can progress into life threatening swelling of the throat; I’m glad I didn’t try treating this with an antibiotic.
How do doctors diagnose bacterial sinusitis?
The gold standard for diagnosing any bacterial infection is to identify the bacteria by growing it in a lab, a test called a culture. For that, we need a sample of the tissue or fluid from the infected area. Since the sinuses are deep in the face, there is no easy way to do this. So most of the time we rely on symptoms and exam. We look for
- Nasal congestion and/or drainage, which can be any color
- Pain and/or pressure in the sinus area including teeth
- Fever, which is a temperature above 100 degrees F or 37.7 C
- Symptoms have been present at least 7 days without improving
Fever- Keep calm and …
Fever- act on the facts not the fallacies; learn how here #fever#seizures
When someone has severe, persistent, or recurrent symptoms suggestive of sinusitis, a physician might obtain xrays, a CT or MRI scan, or look into the sinuses with a scope.
Consider prescribing an antibiotic for sinusitis when–
- Symptoms have been present 10 or more days, and/or are worsening
- Severe symptoms, such as pain not relieved with mild pain meds or persistent fever,
- People with conditions that impair their immune systems, like cancer and its treatment, or people with diabetes
- People with allergic rhinitis often seem to be more prone to bacterial sinus infections or take longer to get better
These of course are all general guidelines; every patient, every illness is different, so different approaches may be needed. This is a framework for us to work from, not hard and fast rules.

Home care for sinusitis
Other ways to feel better when treating sinus infections as well as colds, allergic rhinitis, bronchitis and influenza include rest, increasing oral fluids, and moisturizing the nose and sinuses. (The following includes affiliate links that may pay this blog a commission at no additional cost to you. )
Portable humidifiers are an easy way to relieve dryness in the nose and sinuses.
A Neti pot or sinus rinse bottle are safe, easy ways to relieve dryness, congestion and clear out excess mucous from the nose and sinuses. Always use distilled or boiled water and ask your doctor before using.
Here is a helpful PDF about allergies, colds, and sinusitis
exploring the HEART of health

Thanks,
Dr. Aletha
This is really good information. Thanks for sharing with us. My little ones have been fighting colds for weeks now, but they haven’t developed a fever and seem to be improving. This time of year is rough with children passing illnesses back and forth.
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I remember those days well when my sons were kids. I stay a lot healthier now that they are grown. But some would say it’s good for kids to get exposed to germs, it stimulates their immune systems and makes them more resilient in the long run. Hang in there, you will all get through these difficult years.
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i was once or twice diagnosed with allergic rhinitis – not a nice thing…
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I agree, I have allergic rhinitis as do my son and grandchildren. I am glad there are more effective meds available now than when I and even my son were children. Still, it can be a difficult problem to control, especially if you like to be outdoors much. I hope you have found treatments that keep it controlled for you. Thanks for visiting.
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great post, I love this so much.
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Thank you
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