Your Health A-Z


Sinusitis, inflammation of the paranasal sinuses, is a common disease that may afflict people throughout their lives.


  • Sinusitis is inflammation of the paranasal sinuses (air-filled cavities inside the bones of the skull).
  • Sinusitis may be acute or chronic, and infectious or non-infectious.
  • Anything interfering with airflow into and drainage of mucus out of the sinuses can cause sinusitis.
  • Symptoms include headache, nasal stuffiness, facial tenderness, sore throat, cough, worsening of allergies and purulent nasal discharge.
  • Although rare, sinus infections can cause serious complications, including spread of infection and exacerbation of respiratory tract conditions.

Sinusitis, inflammation of the paranasal sinuses, is a common disease that may afflict people throughout their lives.

What is the Prevalence of sinusitis?

Sinusitis is a common condition, affecting approximately 30% of the population at some point. Sinusitis can occur in infants and children, but is more common in adults as sinuses are undeveloped in infants and start forming during childhood. The average adult has 3-4 upper respiratory infections each year, about 1% of which are complicated by sinusitis. In addition to sinusitis associated with viral respiratory infections, many more people suffer inflammation of the sinuses because of seasonal allergic problems.

The paranasal sinuses and sinusitis

The paranasal sinuses are air-filled cavities inside the bones of the skull. They are located on either side of the nose, behind and between the eyes, and in the forehead; there is also one further back in the head. They probably function to reduce skull weight and to enhance vocal resonance. They also have a protective function, as they absorb severe impact from the front and prevent it being transmitted to the brain.

They are lined with mucus-secreting cells, and they warm, moisten and filter air breathed in. Air reaches the sinuses through small openings in the bones (ostia) that connect to the nasal passageways. The mucus-producing cells have small hairlike fibres (cilia) that beat back and forth to help mucus move towards the ostia and out of the sinuses. If these openings become blocked, air can’t properly pass into the sinuses and mucus can’t drain out. Mucus builds up in the sinus, causing pressure or pain. Also, the mucus is an excellent culture medium for bacteria, and infection can result.

The Course of sinusitis

Typically, early in the development of a sinus infection, the cilia lining the sinuses are lost and mucus becomes increasingly thick. Consequently, mucus is retained in the sinus. If the sinus infection lasts long enough, the sinus lining may physically change, causing even thicker mucus to develop. Bacteria become trapped and proliferate. Once this happens, antibiotics will be needed, and possibly surgery.

Types of sinusitis

Sinusitis may be classified based on time span of the problem (acute, sub-acute or chronic), and the type of inflammation (infectious or non-infectious).

  • Sinus headache – typically lasts a few hours until the ostia unblock and allow equalisation of air pressure in the sinus.
  • Acute sinusitis – typically lasts up to a month.
  • Sub-acute sinusitis – lasts longer than one month, but less than three months’ duration.
  • Chronic sinusitis – longer than three months’ duration.
  • Infectious sinusitis – usually caused by bacterial growth.
  • Non-infectious sinusitis – caused by irritants and allergic conditions.
  • Acute sinusitis is commonly secondary to either allergic rhinitis (hay fever) or viral infection of the nasal passages. Sub-acute and chronic forms of sinusitis usually result from incomplete treatment of acute sinusitis.

The most common complaint is that of a sinus headache. This occurs typically occurs as a result of nasal congestion or sinus mucus which obstructs the ostea, leading to a blockage of air flow and equalisation of air pressure in the sinus and the environment. The air in the sinus is absorbed which causes a negative pressure in the sinus, leading to symptoms of a sinus headache.

Once the obstruction is relieved, the pressure equalises and the sinus headache improves immediately. The second most common cause for sinus symptoms is when the sinus starts producing mucus in response to irritation or constant blockage. At this stage an antibiotic is not usually required. Infection of the sinus usually is accompanied by a temperature, which may suggest that an antibiotic is required.

What causes sinusitis?

  • Anything interfering with airflow into and drainage of mucus out of the sinuses can cause sinusitis.
  • The sinus openings may be obstructed by anything, causing swelling of tissue lining the ostia and adjacent nasal passage, such as colds, allergies and tissue irritants (such as over-the-counter nasal sprays, cigarette smoke and recreational substances snorted through the nose).
  • Allergies may complicate sinusitis.
  • Drainage of mucus can be impaired by thickening of secretions, decrease in mucus hydration (water content) because of disease, drying medications (antihistamines), and lack of air humidity.
  • Irritants, especially smoke, may damage cilia, and prevent them from assisting with mucus drainage. Stagnated mucus provides an ideal environment for bacteria and in some cases (such as AIDS) fungus to grow.
  • Other irritants include car exhaust, petrol and paint fumes, perfume, insect spray and household chemicals.
  • Sinuses can become obstructed by tumours or growths. Nasal polyps (growths arising from mucous surfaces), probably caused by nasal inflammation, can block the ostia.
  • Occasionally, immune problems cause sinus infections. If you have persistent sinus infections, have your immune system evaluated by an allergist/immunologist, especially before surgery is done. You may need allergy tests, and tests to ensure you can form antibodies to common bacteria normally. Sinusitis can be due to AIDS, although only an extremely small percentage of people with sinusitis have AIDS.

Risk factors

  • People with allergies (which cause nasal congestion) are at higher risk of developing sinus headaches and sinusitis.
  • Smokers (tobacco smoke irritates the nasal passages and lowers the body’s natural resistance) are also prone to sinusitis.
  • People in professions where they are often exposed to infection, such as health care workers, are most likely to get sinusitis.
  • Certain anatomical variations, such as a deviated nasal septum, or abnormal turbinates, may make the ostia vulnerable and the patient more susceptible to obstruction of the ostia and result in sinusitis.

When to see a doctor

Although rare, serious complications can result from sinus infections. These include direct extension of infection to the brain and eyes, and blockage of vessels in the head. Erosion of bone can occur if infection eats through the sinuses. Untreated sinusitis can lead to acute bronchitis, ear infection and pneumonia. In certain cases, medical attention is needed.

Call your doctor if:

  • Cold symptoms last longer than 10 to 14 days or worsen over time.
  • You have a severe headache that is not relieved by acetaminophen, aspirin, or ibuprofen or a decongestant.
  • There is increased facial swelling, or changes in vision.
  • Nasal discharge changes from clear to yellow or green after five to seven days of a cold, and other symptoms (such as sinus pain or fever) are worsening. If nasal discharge is coloured from the start of a cold, call if it lasts longer than 7 to 10 days.
  • Facial pain, especially in one sinus area or along the ridge between the nose and lower eyelid, persists after 2 to 4 days of home treatment. If you also have a fever and coloured nasal discharge, call in 1 to 2 days.
  • Sinusitis symptoms persist after a full course of antibiotics.

How is it diagnosed?

After your doctor takes a careful history and performs a physical exam, the diagnosis is typically made by the combination of symptoms and the physical examination. Your doctor may look inside the nose with a flexible rubber or rigid steel tube called an endoscope. This is not painful but might be slightly uncomfortable. Your nose is sprayed first with local anaesthetic. Physical findings may include redness and swelling of the nasal passages, purulent (pus-like) drainage, tenderness to percussion (tapping) over the cheeks or forehead region, and swelling around eyes and cheeks.

An X-ray may be done to confirm whether mucous is present in the sinuses. Depending on what is found at the time of the endoscopy, a computerised axial tomography (CAT) scan of your sinuses may be needed. If you need to have surgery, a CAT scan will ordinarily be done prior to surgery. CAT scans and magnetic resonance imaging (MRI) scans are much more sensitive in their ability to diagnose sinusitis, but are expensive.

Rhinoscopy, a procedure for looking into the back of the nasal passages with a small flexible fiber-optic tube, may be used to look directly at the sinus openings and check for obstruction.

It may sometimes be necessary to perform a needle aspiration (drawing of fluid) of a sinus to confirm the diagnosis of sinusitis, and to collect infected material. This will be cultured so the bacteria causing the infection may be identified.


For negative-pressure sinus headaches, an oral decongestant may be all that is required to relieve the headache. If an underlying hayfever is present, then this will need treatment. This may require the addition of a nasal steroid spray.

It is important to treat a sinus infection as soon as it starts. Treatment involves controlling the source of sinus infection, re-establishing proper nasal drainage, and relieving pain.


  • The following methods of home treatment may get sinuses draining normally again.
  • Drink extra fluids to thin mucus. Drink at least 8 glasses (15 to 20 ideally) of water per day. Some sinusitis medications may make you thirsty.
  • Breathe moist air from a humidifier, hot shower, or sink filled with hot water. Increase home humidity, especially in the bedrooms. (If you are allergic, keep humidity under 50% to prevent mould and dust mite growth.)
  • Use oral decongestants, or mucus-thinning agents. Decongestant nasal sprays may offer temporary relief. However, preferably do not use this treatment unless essential and then do not use for longer than 3 days as this often results in “rebound” – a situation where the nasal obstruction is worse when the decongestant nasal spray’s effect starts wearing off . Avoid products containing antihistamines.
  • Take aspirin, acetaminophen (paracetamol) or ibuprofen for headache.
  • Check the back of your throat for postnasal drip. If streaks of mucus appear, gargle with warm water to prevent a sore throat.
  • Elevate your head at night.
  • Buffered Saline (salt-water + bicarbonate of soda) irrigation helps wash mucus and bacteria out of the nasal passages. Use a bulb syringe to gently squirt the solution into your nose, one nostril at a time with your head bent forwards to encourage the solution to go into the roof of your nose. Sniff it through and then spit it out. Blow your nose gently afterwards. Repeat 2 to 4 times a day.
  • Try to keep your nose clear so you can breathe through it. Air exchange into the sinuses occurs twice as rapidly with nasal breathing as with mouth breathing. Air exchange reduces the likelihood of bacteria growing in the sinuses.
  • Avoid alcohol. It functions as a diuretic, i.e. it may cause dehydration, leading to drying and thickening of mucus. This may in turn cause blockage of the ostia and worsen infection. Allergies or intolerances to red wine, yeast, sulphites or other components of alcohol may compound the problem by causing allergic swelling of the nose.
  • Breathing in eucalyptus oils may help open the nose in some cases.
  • Some people report that breathing in garlic fumes helps.
  • Several non-traditional treatments have been used in the treatment of sinusitis. Acupuncture has been claimed to help the condition, but no studies confirm this.
  • Non-drug treatments should be used together with prescription medication to avoid serious complications.


Again, for negative-pressure sinus headaches, an oral decongestant may be all that is required to relieve the headache.

Acute sinusitis is usually treated with antibiotic therapy aimed at fighting the most common bacteria known to cause sinusitis, since it is usually not possible to get a reliable culture without aspirating the sinuses.

Commonly used antibiotics such as penicillin, erythromycin and tetracycline may not work if the bacteria have become resistant. Antibiotics such as amoxicillin and sulfa drugs may be used as first-line treatment for uncomplicated acute sinus infections, but commonly do not work in people who have had infections for more than a short period or who have been on multiple antibiotics previously. It may then be necessary to use one of the newer antibiotics.

Because antibiotics penetrate poorly into the sinuses, extended treatment is often necessary. Sometimes several different antibiotics are used until the correct one is found. In some cases multiple antibiotics are used. If you are not improving after five days of treatment with amoxicillin, your doctor may decide to switch you to another antibiotic. Generally an antibiotic must be continued for at least 10 to 14 days. It is, however, not unusual to have to continue treatment for sinusitis up to 6 to 8 weeks. Fungal infections of the sinus are common and a specific treatment for this may be required.

Although antibiotics are important in sinus infection treatment, mucus must be allowed to drain adequately. This is done by using nasal sprays containing small amounts of cortisone to reduce inflammation inside the nose and around the ostia.

Oral decongestants (pseudoephedrine) and mucolytics (guaifenesin), used according to directions for 3 to 7 days, may help with sinus drainage. Nasal decongestant spray should be avoided or used sparingly. Take care to prevent worsening of symptoms or addiction to these sprays.

Rarely, antihistamines are used, but only if allergies play a prominent part in symptoms. Antihistamines can be drying, and should be avoided in sinusitis treatment, if possible. Mucus may dry out and become plastered against the sinus wall, trapping bacteria. People feel better initially while fluid volume in the sinuses is reduced, but eventually symptoms return. A topical nasal steroid spray should reduce swelling in the allergic individual without the antihistamine drying effect.

Treatment of chronic sinusitis requires longer courses of drugs, and may require a sinus drainage procedure.

Approximately two-thirds of people with sinus infections have side effects from medications, including dizziness, difficulty concentrating, jitteriness, rapid heartbeat, difficulty sleeping, nausea, bloating, rectal itching, burning on urination, and fatigue. Several of these symptoms can also be due to sinusitis. It is important to schedule follow-up visits to ensure treatment has been adequate. The most common reason people develop future problems with sinus infections is that they stop medications too soon.

If you are allergic and have chronic or recurrent sinusitis, it may help to get desensitisation allergy injections. Allergy injections are required for 36 months and can start working within six to 24 months, and must be used together with other treatment, including control of exposure to environmental allergy-causing agents.


A small percentage of chronic sinusitis sufferers will not improve, even with good medical treatment. In such cases, surgery may be necessary.

The surgery, called functional endoscopic sinus surgery, may be done under local or general anaesthesia. The operation takes approximately 2 to 3 hours. During this time, the surgeon may perform procedures such as straightening the septum, removing tissue from inside the nose, making an opening into the sinus(es) on either side of the nose to improve drainage, and removing some of the inflamed sinus lining. The number of sinuses opened up depends on the nature of your problem. The surgeon inserts a rigid tube (endoscope) into the nose. The entire operation is done through the nose.

You will generally stay in hospital for the day of the operation, or sometimes overnight. You will probably miss 1 to 2 weeks of work. Full recovery may take 6 weeks, although for 6 months to a year you may be more sensitive to infection. If you aren’t better at that point, you may have allergies, immune problems, fungal infection of the sinuses, scarring from the original surgery, or sinusitis involving sinuses other than those originally operated on. The surgeon will typically remove crusting from the nose to prevent scarring. For a short period while healing occurs, there will be limitations on lifting, blowing the nose, and flying. Most people don’t have a much pain, but if you do, ask your doctor for pain medication.

Having surgery does not necessarily mean you won’t get sinusitis again, but it often becomes easier to treat. Once the sinuses are surgically opened, it is possible to wash them out, and as a result, sometimes oral antibiotics become unnecessary. After surgery, it often becomes easier to perform endoscopy and find out exactly where the cause of the problem is.

Treatment of polyps involves steroids, treatment of sinusitis, and treating any allergies. They may sometimes need to be removed surgically, but may come back. They are usually not pre-cancerous.

Prevention of sinusitis

  • Once your sinus infection has been treated, it is important to try to prevent infections. The more frequently sinus infections occur, the more likely future surgery becomes.
  • Treat colds and allergies promptly.
  • Blow your nose gently. Do not close one nostril when blowing your nose.
  • Drink plenty of extra fluids when you have a cold, to help keep mucus draining.
  • Stop smoking. Smokers are more prone to sinusitis.
  • If you have underlying hayfever, have this treated optimally and institute allergen avoidance measures.

Updated June 2007

The information provided in this article was correct at the time of publishing. At Mediclinic we endeavour to provide our patients and readers with accurate and reliable information, which is why we continually review and update our content. However, due to the dynamic nature of clinical information and medicine, some information may from time to time become outdated prior to revision.

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