Does Rhinitis Turn Into Sinusitis? Signs, CT and Treatment

Hello. I am Shunichi Gamo, MD, PhD, a board-certified allergist and pulmonologist and the director of Sendai Airport North Clinic.

With the temperature swings of the changing seasons, more people have a runny or stuffy nose that will not go away. In the clinic, people with allergic rhinitis and people who have just had a cold often ask me something like this.

“I thought it was just rhinitis and ignored it, and now the yellow nasal discharge and the heavy feeling in my face will not go away.”

Let me start with the conclusion: when rhinitis drags on, it can turn into sinusitis. Roughly speaking, swelling of the lining of the nose blocks the openings of the sinuses, mucus collects inside, and the inflammation spreads[1][2].

This article explains how rhinitis can lead to sinusitis and the guideposts for suspecting bacterial sinusitis. It also covers why treating allergic rhinitis matters, and why CT (computed tomography, an imaging test that takes detailed cross-sectional pictures of the body) is better suited for imaging.

I will explain this in plain terms from the viewpoint of a pulmonologist. Also, PCR (a test that amplifies the genetic material of viruses and other germs in order to detect them), mentioned in the Sunday and holiday notice below, is the test used in our fever clinic.

From October 4, 2026, we also run the fever clinic on Sundays and holidays
10:00 to 15:00 (no lunch break). No appointment is needed; you are seen by checking in on the day. We tell you the PCR test result on the same day. On Sundays and holidays we run the fever clinic only; there is no general outpatient clinic and no IV drip service. We are closed on Sunday, October 25, and from November the clinic is open on Sundays and holidays as a rule. Notice about the Sunday and holiday fever clinic

Why does rhinitis that drags on turn into sinusitis?

Rhinitis that drags on can turn into sinusitis because the swollen mucous membrane (the soft lining of the inside of the nose) blocks the openings of the sinuses. The paranasal sinuses are four air-filled spaces in the bones around the nose[3].

They are the maxillary sinus (behind the cheeks), the ethmoid sinus (between the eyes), the frontal sinus (behind the forehead), and the sphenoid sinus (deeper still)[3].

Each sinus connects to the inside of the nose through a narrow opening called the ostium[1]. The guideline (a set of clinical recommendations compiled by a medical society) also names the narrow ostium and the swollen lining around it as the place that treatment needs to address[1].

When rhinitis (inflammation of the lining of the nose) swells the mucous membrane, these openings become narrower. Air exchange and mucus drainage inside the sinus then get worse, and inflammation tends to continue in the mucus that has collected[1].

Even with a cold, the sinuses are swollen in most people

In fact, it is known that even an ordinary cold swells the sinuses.

A team at the University of Virginia in the United States examined the nose and sinuses by CT in 31 healthy adults (average age 24) who were 2 to 4 days into cold symptoms[2]. CT is short for computed tomography, and it can show cross-sections in fine detail, even the spaces inside bone.

The passage where the sinus openings gather (the ethmoid infundibulum) was blocked in 77% of the people[2]. An abnormality of the maxillary sinus behind the cheeks was found in 87%, and an abnormality of the ethmoid sinus between the eyes in 65%[2].

When 14 of them had CT again two weeks later, the abnormalities had disappeared or improved greatly in 79%[2]. This means that much of the “sinus swelling” in the first few days of a cold is an extension of the rhinitis and goes down over time[1][2].

The problem is when the swelling does not go down, bacteria multiply in the trapped mucus, and the condition progresses to “bacterial sinusitis.”

What is sinusitis? How is it different from rhinitis?

Sinusitis is a condition in which inflammation occurs inside the sinuses around the nose, and in the past it was also called “chikunosho” (empyema of the sinuses)[3]. Rhinitis is inflammation of the lining inside the nose, while sinusitis is the state in which the inflammation has spread to the spaces behind it.

The symptoms of acute sinusitis are a blocked nose, thick and foul-smelling nasal discharge, pain in the cheeks, around the nose, or in the forehead, swelling of the face or eyelids, and fever[3]. The guideline of the Japanese Rhinologic Society defines acute sinusitis as “an infection of the nose and sinuses within 4 weeks of onset”[1].

	Rhinitis	Sinusitis
Where the inflammation is	The lining inside the nose	The air-filled spaces in the bones around the nose (sinuses)
Nasal discharge	Often clear and watery (allergic rhinitis)	Thick yellow to green discharge, discharge that drips down the throat
Pain and heaviness	Often not noticeable	Pain in the cheeks, forehead, or behind the eyes; a heavy, pressing feeling in the face
Other	Sneezing, itchy nose (allergic rhinitis)	Fever, a poor sense of smell, pain in the upper back teeth

It is not decided by the character of the discharge alone; we judge it together with how the illness has progressed. The guideline also lists fever, redness of the face, and pain in the upper back teeth as symptoms that make acute sinusitis more likely[1].

How can you tell a cold-related rhinitis from bacterial sinusitis? Three guideposts

The basic way to tell a cold-related rhinitis from bacterial sinusitis is the “course of the symptoms.” The guideline of the Japanese Rhinologic Society says that most viral sinusitis gets better within 10 days[1]. If a blocked nose or facial pain is hard to bear, there are treatments that ease the symptoms, so please talk to us.

On top of that, the guideline says that when purulent (pus-like) nasal discharge lasts 10 days or longer, or when things get worse after 5 to 7 days, it is diagnosed as bacterial sinusitis caused by a secondary bacterial infection. Bacterial sinusitis is also suspected when high fever and purulent nasal discharge occur together for 3 to 4 days (this description is for children)[1].

For the third item, the “high fever” is described as 39°C or higher in the guideline’s explanation of severe symptoms in children[1].

The guideline of the Infectious Diseases Society of America (IDSA) uses almost the same three guideposts[4]. The first is symptoms lasting 10 days or more; the second is a fever of 39°C or higher from the start of the illness together with purulent nasal discharge or facial pain for 3 to 4 days[4]. The third is a cold that lasted 5 to 6 days and was starting to improve, and then fever, headache, or nasal discharge get worse again[4]. These are US criteria, and policies differ by country and by medical institution.

If any one of the three applies, do not assume it is just rhinitis that is dragging on. Please see a doctor early, during clinic hours. Children cannot put facial pain into words, so irritability and a wet cough can also be guideposts[1].

Does allergic rhinitis make sinusitis more likely?

Allergic rhinitis is known to be associated with sinusitis, especially with chronic sinusitis that lasts a long time[5]. Allergic rhinitis is a condition in which the body overreacts to house dust, mites, or Japanese cedar and cypress pollen, causing sneezing, a runny nose, and a blocked nose[3].

With allergic rhinitis, the lining of the nose swells easily during the pollen season, or all year round if mites or house dust are the cause. If swelling from a cold is added on top of that, the sinus openings are likely to become even narrower.

A study that followed people from age 6 to 53: hay fever and asthma were linked to chronic sinusitis

In Tasmania, Australia, a study followed 8,583 people who were 6 to 7 years old in 1968 into middle age[5]. In the middle-age survey, 3,609 took part[5].

At age 53, 5.8% said they currently had symptoms of chronic sinusitis, and 2.5% had both symptoms and a doctor’s diagnosis[5].

People who developed hay fever as adults were linked to chronic sinusitis with both a doctor’s diagnosis and symptoms, with a multinomial odds ratio (a number showing how many times more likely a condition is) of 3.02[5]. The 95% confidence interval (the range in which the true value probably lies) was 1.51 to 6.06; because it does not cross 1, the result is hard to explain by chance alone[5].

For people whose asthma and allergy continued from childhood the figure was 6.74 (95% confidence interval 2.76 to 16.4), and for people who often caught colds in childhood it was 2.04; associations were seen in both[5]. The research team called asthma and allergy “potentially treatable” factors for chronic sinusitis[5].

However, this study looked at “association,” and did not confirm whether treating rhinitis or asthma reduces sinusitis[5]. Even so, keeping rhinitis and asthma well controlled is thought to be a foundation for reducing sinusitis that drags on.

The guideline also says that, when examining sinusitis, it is useful to ask about a history of nasal diseases such as allergic rhinitis[1].

For our allergy care, please also see the Allergy department page.

What is chronic sinusitis? Its link to nasal polyps and asthma

Chronic sinusitis is a condition in which, even after the acute symptoms settle, the person never quite feels clear and the inflammation becomes long-lasting[3]. Be careful when symptoms such as a blocked nose, sticky nasal discharge, a heavy head, or loss of smell continue[3].

Recently, eosinophilic sinusitis, in which many eosinophils (a type of white blood cell involved in allergy) gather, has been increasing[3]. It is characterized by being hard to cure, sometimes occurring together with asthma, loss of smell, and nasal polyps (soft growths that form inside the nose)[3].

Treatments for chronic sinusitis include taking a low dose of a macrolide antibiotic (one type of antibiotic) for a long time, and a nebulizer (a way of inhaling medicine as a mist)[3]. If the condition still does not improve, surgery using an endoscope (a thin camera) is performed[3].

If you have asthma and a blocked nose or reduced sense of smell continues, I recommend having your nose examined as well. The nose and the bronchi are one continuous airway, so it is important to think about both together.

For imaging of sinusitis, is CT better than an X-ray?

For imaging of sinusitis, CT shows more detail than an X-ray (plain radiograph). Because the sinuses are surrounded by bone, the Japanese guideline also states that X-rays have limits for diagnosis[1].

The guideline introduces a study that compared X-ray and CT in acute sinusitis[1]. For shadows in the maxillary sinus behind the cheeks, the X-ray had a sensitivity (the proportion of people with the disease whom a test correctly detects) of 80%[1]. For the other sinuses the sensitivity was low and diagnosis was difficult[1].

This means that the ethmoid sinus between the eyes and the frontal sinus behind the forehead are places that are easily missed on an X-ray.

The imaging guidance of the American College of Radiology (ACR) names CT and MRI (a test that uses magnetism to take cross-sectional pictures of the body) as the main imaging tests for sinus disease[6].

It says that CT shows the shape of the bone in fine detail, so it can accurately show whether there is inflammation in the sinuses, whether bone has been eroded, and congenital differences in shape[6]. MRI is said to be better for seeing spread behind the eyes or into the head[6]. This is US guidance, and policies differ by country and by medical institution.

When is imaging needed?

According to the Japanese guideline, acute sinusitis in adults can be diagnosed from the symptoms, the course, and an examination inside the nose, and treatment can be started[1]. In other words, not everyone with acute sinusitis needs imaging.

On the other hand, when symptoms are severe, when treatment does not help, when the illness keeps coming back, or when complications (other illnesses triggered by the original illness) are a concern, CT gives a lot of information[1]. In children, CT is said to be unnecessary unless complications are suspected[1].

The current thinking is that when a detailed imaging examination is needed, CT, which can show the whole sinus system and the surrounding bone, is the main choice[1][6].

[Go even at night or on holidays, or call 119] Danger signs of sinusitis

The danger signs of sinusitis are swelling around the eyes, changes in vision, and a headache stronger than any you have had before. The sinuses are separated from the eyes and the brain only by thin bone, so in rare cases the inflammation spreads behind the eye (the orbit) or into the head[1].

The guideline says that severe cases can cause orbital cellulitis (an infection of the tissue behind the eye) and other complications[1]. When complications behind the eye or inside the head are suspected, the patient is admitted, given intravenous antibiotics, and surgery is considered[1].

The retina and the optic nerve are easily damaged even by a short lack of oxygen, and if vision is affected, early surgery is said to be needed[1]. For the signs below, go to an emergency department without waiting, even at night or on a holiday.

In addition, if the person is confused or drowsy, slow to respond when called, has had a seizure, or has a stiff neck that cannot bend forward, there is concern that the infection has spread into the head. Call 119 without hesitation.

How is sinusitis treated? Antibiotics and treatment of rhinitis

For sinusitis, antibiotics are the mainstay of treatment if it is bacterial, combined with treatment of the rhinitis. The guideline says that bacterial sinusitis tends to become severe, so it needs early treatment with antibiotics[1].

In the Japanese guideline, an antibiotic treatment period of 7 to 10 days is considered appropriate[1]. The actual number of days is decided by the doctor according to severity and the type of medicine.

When antibiotics are needed, start them without hesitation, and take all of what was prescribed to the end even if you feel better. If you stop partway, the remaining bacteria can come back. Please do not take leftover antibiotics at home on your own judgment.

Treating allergic rhinitis: steroid nasal sprays and antihistamines

The basics of treating allergic rhinitis are avoiding the cause and controlling symptoms with oral medicines or nasal sprays[3]. If the cause is known, there is also a fundamental treatment called allergen immunotherapy (such as sublingual immunotherapy), which gets the body used to the allergen little by little[3].

There is an analysis that compared steroid nasal sprays (steroid medicine sprayed into the nose) with antihistamines (oral medicines that suppress the allergic reaction)[7]. Published in 1998, it combined 16 randomized controlled trials (trials in which treatments are assigned by chance, like drawing lots, and then compared) from around the world, with 2,267 people[7].

This is a meta-analysis (a method of adding up the results of several studies numerically to evaluate them), and a type of systematic review (a method of gathering and evaluating all studies on the same topic)[7]. For a blocked nose, runny nose, sneezing, and itchy nose, steroid nasal sprays improved symptoms more than antihistamines did[7].

A blocked nose is exactly the swelling of the lining that blocks the sinus openings. Controlling the nasal blockage of allergic rhinitis well is considered a sensible way to keep rhinitis from dragging on.

Do steroid nasal sprays also work for sinusitis?

There is a Cochrane review that examined four trials with 1,943 patients with acute sinusitis[8]. Cochrane is an international group that gathers and evaluates medical research.

When three of the trials were combined, the proportion of people whose symptoms resolved or improved was 73% with the steroid nasal spray and 66.4% with placebo (risk ratio 1.11, 95% confidence interval 1.04 to 1.18)[8]. The risk ratio shows how many times larger the proportion who got better became, and the conclusion was that the effect is a “modest but meaningful added benefit”[8].

However, this combines trials from overseas. The Japanese guideline (the 2014 supplement) explains that acute sinusitis is not among the conditions for which steroid nasal sprays are approved in Japan[1]. For people with allergic rhinitis, continuing that treatment is thought to end up protecting the sinus openings as well.

Cautions about over-the-counter nasal decongestant sprays

Some over-the-counter decongestant nasal sprays contain a vasoconstrictor (a medicine that narrows the blood vessels in the nose to reduce swelling). A vasoconstrictor relieves a blocked nose for a while, but the medicine does not reach the sinuses, so it is said not to work on swelling of the sinus lining[1].

If it is used continuously or many times, it works less well, so a rest period is needed[1]. In small children under 2 years old, whole-body side effects appear more easily, and it is preferable not to use it continuously[1].

What to tell the doctor when you see us for sinusitis

When you see a doctor for sinusitis, telling us the following is a shortcut to the diagnosis. It is easier to tell us if you jot it down.

How to see us at our clinic [If you have a fever, come to the fever clinic]

At Sendai Airport North Clinic, nasal and sinus symptoms with a fever are seen in the fever clinic. No appointment is needed; we see you through the pre-visit questionnaire and same-day check-in. Our policy is that we do not turn away anyone who comes to the fever clinic.

If you have no fever but a runny or blocked nose has dragged on, please consult us during the clinic hours below.

Day	Hours
Mon, Tue, Wed, Fri, Sat	9:00 to 12:00 / 14:00 to 18:00
Sundays and holidays (from October 4, 2026)	10:00 to 15:00 (no lunch break, fever clinic only)
Thursday	Closed

For the detailed Sunday and holiday schedule, please see Notice about the Sunday and holiday fever clinic and About the pre-visit questionnaire and same-day check-in for the fever clinic.

How a fever clinic visit works

You check in using the QR code (a square pattern that your smartphone camera can read) at the entrance. When your turn is near, we call you by SMS (text message on a mobile phone) or by phone.

If you have swelling around the eyes, changes in vision, or a headache stronger than any you have had before, go to an emergency department, not our fever clinic. Do not wait, even at night or on a holiday.

Frequently asked questions (FAQ)

What is the difference between rhinitis and sinusitis?

Rhinitis is inflammation of the lining inside the nose, while sinusitis is the state in which the inflammation has spread to the air-filled spaces in the bones around the nose (the sinuses)[3]. When rhinitis swells the lining and blocks the sinus openings, it can progress to sinusitis[1][2].

If I treat allergic rhinitis, can I prevent sinusitis?

The Tasmanian study looked at association, and did not confirm whether treatment can prevent sinusitis. Still, hay fever and asthma are linked to chronic sinusitis, and the research team called them “potentially treatable” factors[5]. Controlling a blocked nose so that the sinus openings are less likely to be blocked is considered a sensible measure.

If I have yellow nasal discharge, is it sinusitis that needs antibiotics?

Yellow nasal discharge also appears early in a cold. The guideposts are three: pus-like discharge lasting 10 days or more, getting worse after 5 to 7 days, or lasting 3 to 4 days together with a high fever[1]. If any applies, see a doctor, and if antibiotics are judged necessary, start them without hesitation and take all that was prescribed to the end.

Can sinusitis only be recognized with a CT scan?

Acute sinusitis in adults can be diagnosed from the symptoms, the course, and an examination inside the nose, and treatment can be started[1]. When symptoms are severe, treatment does not help, the illness keeps coming back, or complications are a concern, CT, which gives more information than an X-ray, is useful[1][6].

Is it all right to keep using an over-the-counter nasal decongestant spray?

Some over-the-counter decongestant sprays contain a vasoconstrictor, which opens the nose for a while but is said not to work on swelling of the sinus lining[1]. With continuous use it works less well and a rest period is needed, so please talk to us if you have been using one for a long time[1].

I started antibiotics a few days ago, but I am not getting better.

Please do not stop on your own; see a doctor again. The guideline also describes a procedure of changing the antibiotic when the first treatment brings no improvement[1]. If you have swelling around the eyes, changes in vision, or a headache stronger than any you have had before, go to an emergency department even at night or on a holiday.

Summary [Do not let rhinitis drag on, and do not miss the signs of sinusitis]

If you ignore it as “just rhinitis,” it can lead to facial pain and nasal discharge that lingers. If nasal symptoms drag on, please talk to us early. Leave the medical care to us.

That’s all.

Disclaimer

This article is intended to provide general medical information and does not replace an examination, diagnosis, or treatment by a doctor. The content is based on medical knowledge at the time of publication, but the appropriate response differs from person to person. If you are worried about your symptoms, please consult a medical institution.

References

1. Japanese Rhinologic Society, Acute Rhinosinusitis Clinical Practice Guideline Committee. Clinical Practice Guideline for Acute Rhinosinusitis 2010 (Supplement). Nihon Bika Gakkai Kaishi (Journal of the Japanese Rhinologic Society). 2014;53(2):103-160. doi:10.7248/jjrhi.53.103 https://www.jstage.jst.go.jp/article/jjrhi/53/2/53_103/_article/-char/ja/ (in Japanese)
2. Gwaltney JM, Phillips CD, Miller RD, Riker DK. Computed tomographic study of the common cold. N Engl J Med. 1994 Jan;330(1):25-30. doi:10.1056/NEJM199401063300105 PMID: 8259141
3. Japan Society of Otorhinolaryngology and Head and Neck Surgery. Common diseases handled by otorhinolaryngology and head and neck surgery: Diseases of the nose (sinusitis and allergic rhinitis). Japan Society of Otorhinolaryngology and Head and Neck Surgery website. Accessed October 2026. https://www.jibika.or.jp/modules/disease/index.php?content_id=21 (in Japanese)
4. Chow AW, Benninger MS, Brook I, Brozek JL, Goldstein EJ, Hicks LA, et al. IDSA clinical practice guideline for acute bacterial rhinosinusitis in children and adults. Clin Infect Dis. 2012 Apr;54(8):e72-e112. doi:10.1093/cid/cir1043 PMID: 22438350
5. Perret JL, Idrose NS, Walters EH, Bui DS, Lowe AJ, Lodge CJ, et al. Childhood infections, asthma and allergy trajectories, and chronic rhinosinusitis in middle age: A prospective cohort study across six decades. Allergy. 2024 Oct;79(10):2717-2731. doi:10.1111/all.16184 PMID: 38987868
6. Expert Panel on Neurological Imaging, Hagiwara M, Policeni B, Juliano AF, Agarwal M, Burns J, et al. ACR Appropriateness Criteria® Sinonasal Disease: 2021 Update. J Am Coll Radiol. 2022 May;19(5S):S175-S193. doi:10.1016/j.jacr.2022.02.011 PMID: 35550800
7. Weiner JM, Abramson MJ, Puy RM. Intranasal corticosteroids versus oral H1 receptor antagonists in allergic rhinitis: systematic review of randomised controlled trials. BMJ. 1998 Dec;317(7173):1624-9. doi:10.1136/bmj.317.7173.1624 PMID: 9848901
8. Zalmanovici Trestioreanu A, Yaphe J. Intranasal steroids for acute sinusitis. Cochrane Database Syst Rev. 2013 Dec;2013(12):CD005149. doi:10.1002/14651858.CD005149.pub4 PMID: 24293353

Related articles for when nose or throat symptoms continue

For the Sunday and holiday fever clinic, see Notice about the Sunday and holiday fever clinic; for how to visit, see About the pre-visit questionnaire and same-day check-in for the fever clinic.