Sinusitis 

Sinusitis is inflammation (swelling) of the lining of the sinuses, caused by a viral or bacterial infection.

The sinuses are small, air-filled cavities behind your cheekbones and forehead (see below). 

Sinusitis typically causes a high temperature, pain and tenderness in the face, and a blocked or runny nose (see Sinusitis symptoms).

It is a common condition and can affect people of any age.

The sinuses

You have four pairs of sinuses in your head:

• two sinuses behind your forehead
• two at either side of the bridge of your nose
• two behind your eyes
• two behind your cheekbones

Your sinuses open up into the cavity of your nose and help control the temperature and water content of the air reaching your lungs. 

Usually, the mucus naturally produced by your sinuses drains into your nose through small channels. These channels can become blocked when the sinuses are infected and inflamed.

It is the sinuses behind the cheekbones (the largest ones) that are most commonly affected.

Acute and chronic sinusitis

Sinusitis is classed as either:

• acute, when it develops quickly (over a few days) following a cold or flu and clears up within 12 weeks, or
• chronic, when symptoms last for more than 12 weeks.

Chronic sinusitis is less common and can sometimes last for many months.

Outlook

Sinusitis often clears up by itself, and about two thirds of those who get the condition do not need to see their GP.

On average, sinusitis takes about two-and-a-half weeks to clear.

Over-the-counter painkillers and decongestants can be used to relieve facial pain and a blocked nose. Antibiotics are unlikely to help unless the sinusitis becomes persistent.