How is sinusitis diagnosed?

Your doctor may ask you some questions about your health, for example, what your symptoms are, if you have had a cold recently, or if you have a history of hay fever, allergies, or any other medical conditions. This is often all they need to do to make the diagnosis.

Laboratory tests

Your doctor may also take a small sample of mucus or cells from the inside of your nose using a sterile cotton swab, which can be sent to a laboratory to find out what is causing the infection.


X-rays are not usually used to diagnose a sinus infection because the X-ray is not usually helpful in confirming the diagnosis.

Computerised tomography (CT) scans

CT scans will only be used if a specialist considers it is necessary to diagnose your illness. Children should only have a CT scan if it is really necessary. This is because the CT scan involves a large dose of radiation, and there is a risk this may affect the lens of the eye.

A CT scan may be recommended if:

  • you have already had antibiotics for a suspected sinus infection but you still have symptoms
  • you have symptoms that are not typical of sinusitis or another respiratory infection
  • your symptoms are very severe
  • you only have symptoms on one side of your head
  • there is blood in the mucus or liquid in your nose
  • the pain in your head or face is severe
  • the position of one of your eyes is affected.
  • Respiratory Expert Group. Therapeutic Guidelines. Respiratory: Rhinosinusitis. Melbourne: Therapeutic Guidelines Ltd; March 2012. (Accessed 27 March 2012).