What does this mean?
In a healthy nose the two sides take turns. The blood vessels inside the nose swell and shrink, changing sides every few hours, so the side that feels more blocked shifts on its own through the day. Most people never notice this. A blockage that stays on the same side suggests that a local obstruction has been added on top of that natural cycle.
What sets this symptom apart from similar ones is that the side does not change. Allergy and a common cold usually affect both nostrils, and a cold settles within a few days. A blockage that stays on the same side for weeks points instead to an obstruction on that side: a deviated septum, a polyp, enlarged adenoids or inflammation filling the maxillary sinus, the air space that sits above your upper back teeth. The roots of the upper molars lie very close to the floor of this sinus, and inflammation coming from a root can fill it on one side only.
When the blockage started is a guide too. A one-sided blockage that began after an upper back tooth was taken out, or after root canal treatment, brings to mind an opening left between the mouth and the sinus. In a child, a blockage that starts suddenly on one side and smells is a reason to think of an object pushed into the nose. In an adult whose nose has been blocked on the same side for a long time and whose discharge has blood in it, the assessment is carried out by an ENT specialist.
With a one-sided blockage the first job is to work out whether the obstruction lies inside the nose itself or in the maxillary sinus. The headings below are not a ranking by likelihood; they are a list of the places that get looked at.
Likely causes
What helps at home?
- You can keep the inside of your nose moist with a saline spray or a ready-made rinse; this does not change the cause, but it makes things easier until you are seen.
- Do not use decongestant nasal sprays for longer than three days; with longer use, the blockage commonly comes back worse once the spray is stopped.
- Write down which side is blocked, when it started, and whether anything has been done to your upper back teeth in the past year; that record is useful at the examination.
- Do not try to clear your nose by putting anything into it, or by closing one nostril and blowing hard; the lining bleeds easily and the pressure rises towards the sinus.
- If the blockage comes with repeated nosebleeds from the same side
- If swelling has appeared in your cheek or around your eye on that side
- If your eyelid has dropped, you are seeing double, or your eye looks pushed forward
- If a fever, a severe headache and a stiff neck have been added
- If the blockage has been on the same side for more than three weeks and is not settling
Frequently asked questions
- Can a blocked nose on one side come from my tooth?
- It can. The roots of the upper molars and premolars lie very close to the floor of the maxillary sinus. If inflammation coming from a root thickens the lining of the sinus, the blockage settles on that side and most of the time goes along with a bad smell. A dental examination and the right imaging show whether the source is in a tooth. Even so, not every one-sided blockage is caused by a tooth; a deviated septum and polyps are common too.
- I have taken medication, so why does the blockage keep coming back?
- Treatments aimed at the sinus reduce the swelling in the lining. If what keeps the blockage going is a structural obstruction, or a source that keeps feeding the sinus, then the picture returning once the medication runs out is what would be expected. That is why, with a one-sided blockage that keeps coming back, it is not only medication but the search for the source that comes onto the agenda.
- Should I see an ENT specialist first, or a dentist?
- Either is a reasonable starting point. If the blockage started after work on an upper back tooth, is on one side and comes with a smell, beginning with a dental examination can save time. If there is bleeding, a reduced sense of smell or numbness in the face, the assessment is taken on by an ENT specialist. These two fields most of the time deal with the same patient together.
This content is for general information and does not replace an in-person examination. Symptoms overlap between conditions, and a diagnosis can only be made clinically.