Description, causes, prevention, treatment and medicines

Sinusitis is inflammation of the sinuses that surround the nose (paranasal sinuses), and is usually accompanied by rhinitis – inflammation of the lining of the nose. This is known as rhinosinusitis.

Sinusitis is defined as either:

  • acute (symptoms come on suddenly); or
  • chronic (symptoms last for longer than 12 weeks).


The main symptoms of sinusitis include:

  • pain or pressure felt in the face;
  • either blocked nose or runny nose and/or postnasal drip (mucus running down the back of the throat causing irritation); and
  • reduced sense of smell or taste.

Additional symptoms may include:

  • facial tenderness;
  • fever;
  • tiredness;
  • bad breath;
  • headache;
  • swelling around the eyes;
  • pain in the upper jaw and/or teeth;
  • cough; and
  • nausea.

Symptoms of chronic sinusitis are similar to those of acute sinusitis, but last longer. Fever is generally not a feature of chronic sinusitis.

A sensation of partial deafness or blockage in the ear may also occur. This is because the Eustachian tube, which connects the middle ear to the back of the nose, blocks up in just the same way as the nearby sinus openings.

The sinuses

The paranasal sinuses are spaces in the bones of the skull which are mainly full of air. The paranasal sinuses include:

  • the sphenoid sinus – in the centre of the head;
  • the maxillary sinuses – situated in the cheekbones;
  • the frontal sinuses – above the eyes; and
  • the ethmoidal sinuses – on either side of the nose.

The lining of the sinuses produces clear fluid – mucus – which cleans them. This fluid passes through narrow drainage passages into the back of the nose and throat, from where it is swallowed. This happens continually, although we are usually unaware of it.

Because the drainage holes from the sinuses are narrow, they block up easily. So any excess mucus production can cause a blockage, and pressure builds up in the sinuses.

The 2 main causes of excess mucus production are:

  • infection; and
  • allergy.


Causes of infective sinusitis include:

  • viral infections such as the common cold;
  • bacterial infections (usually a complication of viral sinusitis);
  • fungal infections (usually seen in people with an underlying problem with their sinuses or immune system).

Risk factors

Factors that can increase your risk of developing sinusitis include:

  • obstruction in the nose or sinuses (due to problems such as nasal polyps – small benign growths in the nose, or a deviated septum after a fractured nose);
  • allergy (hay fever, or allergic rhinitis); and
  • problems with your immune system.

Tests and Diagnosis

Your doctor will usually be able to diagnose sinusitis based on your symptoms and physical examination. In some cases, tests may be necessary if the sinusitis is persistent.

Tests that can help diagnose sinusitis and determine the cause include:

  • Imaging tests, such as CT scan or MRI (magnetic resonance imaging) of the paranasal sinuses, are sometimes used when symptoms are severe or chronic sinusitis is not improving.
  • Nasal endoscopy, where a narrow lighted tube with a camera is used to look at the nasal cavity and sinuses. It can show excess mucus, inflammation and swelling of the inner lining of the nose and sinuses, and problems such as polyps.
  • Microbiology tests: a nasal swab is sent for testing to try to confirm if there is an infection and what type. This type of test is only performed when sinusitis is not responding to treatment.
  • Allergy tests, to determine whether allergies are contributing to your sinusitis.


Treatments for sinusitis include:

  • Self-care measures such as rest, drinking plenty of fluids, steam inhalations, and applying a warm compress to your forehead.
  • Pain relievers such as paracetamol and non-steroidal anti-inflammatory drugs (NSAIDs).
  • Saline nasal sprays and nasal irrigation are useful in relieving nasal congestion.
  • Corticosteroid nasal sprays can also help improve symptoms. Oral corticosteroid tablets are also occasionally used to treat acute and chronic sinusitis.
  • Decongestants: decongestant nasal sprays can provide relief but should not be used for longer than 3 days or in young children. Decongestant tablets can also be used to ease symptoms, but should not be used for more than a few days.
  • Hay fever treatment, including antihistamine nasal spray or tablets, is recommended when allergic rhinitis is contributing to sinusitis. Immunotherapy for ongoing hay fever is another treatment option.


Antibiotics are sometimes needed to treat sinusitis when a bacterial infection is suspected. Acute bacterial sinusitis is suspected when:

  • symptoms are getting worse after initial improvement;
  • you have a high fever, symptoms are severe and have lasted for more than 3 days; or
  • symptoms of rhinosinusitis have lasted for longer than 7 days.

Chronic sinusitis may also sometimes need antibiotic treatment.


Sometimes surgery is necessary to drain a chronically blocked sinus, or to enlarge the drainage passage. This is most commonly done using an endoscope (a thin, flexible tube with an attached light), which is passed through the nose.

When to see your doctor

Acute sinusitis that is caused by a virus usually resolves in 7 to 10 days. If you have symptoms that are severe, have not resolved, have returned, or are getting worse, see your doctor.

If you have chronic sinusitis and treatments are not helping, your doctor may refer you to a specialist – such as an Ear, Nose and Throat (ENT) specialist or an Allergy specialist – for further evaluation and treatment.

Spread of infection into nearby structures, such as the eye or brain, is a serious but rare complication of untreated bacterial sinus infections.

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