Inflammation of any of the sinuses (the air-filled cavities in the bones around the nose)

  • More common in adults
  • Genetics as a risk factor depends on the cause
  • Gender and lifestyle are not significant factors

The sinuses are air-filled cavities in the skull situated behind the nose and eyes and in the cheeks and forehead. They are lined with a mucus-secreting membrane and are connected to the nasal cavity by a number of narrow channels. Inflammation of the sinuses, known as sinusitis, may be acute (developing and clearing up rapidly) or chronic (long-term). Sinusitis rarely occurs in children under the age of 5, partly because their sinuses are not fully developed.

What are the causes?

The most common cause of sinusitis is a viral infection, such as the common cold. If the channels connecting the nose to the sinuses become blocked due to the viral infection, mucus collects in the sinuses. In some cases, the mucus becomes infected with bacteria.

Blockage of the channels is more likely in people with an abnormality in the nose, such as a deviated nasal septum or nasal polyps. In addition, people with allergic rhinitis or a disorder such as the inherited condition cystic fibrosis are more likely to develop sinusitis. Rarely, the channels are blocked by a tumour (see Cancer of the nasopharynx). People with reduced immunity and those taking immunosuppressant drugs, are more susceptible to infections that lead to sinusitis.

What are the symptoms?

Symptoms depend on which sinuses are affected and may include:

  • Headache.

  • Pain and tenderness in the face that tends to worsen when bending down.

  • Toothache, if the sinuses behind the cheeks are affected.

  • Discoloured nasal discharge.

  • Nasal congestion or obstruction.

In a few cases, the infection spreads and may cause redness and swelling of the tissue around an eye.


This colour-enhanced facial X-ray shows a normal air-filled sinus and a sinus filled with mucus, indicating sinusitis.

What can I do?

In many cases, sinusitis clears up without treatment. Painkillers and decongestants, both available over the counter, may alleviate symptoms. Steam inhalation, which usually helps to clear the nose, may also relieve symptoms. If symptoms become worse or do not improve within 3 days, you should consult a doctor.

What might the doctor do?

Your doctor may prescribe antibiotics to clear up secondary bacterial infection. If sinusitis recurs or does not clear up completely, you may have X-rays to look for thickening of the lining of the sinuses and excess mucus. Your doctor may also perform endoscopy of the nose (see Endoscopy of the nose and throat) and arrange for CT scanning to look for a specific cause, such as nasal polyps or a tumour. Surgery may be necessary to enlarge drainage channels from the sinuses to the nose or create new ones. Acute sinusitis usually clears up in a few days, but the symptoms of chronic sinusitis may last for a couple of months.

Self-help: Steam Inhalation

Test: Endoscopy of the Nose and Throat

From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.

The subjects, conditions and treatments covered in this encyclopaedia are for information only and may not be covered by your insurance product should you make a claim.

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