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Sinus infection (Sinusitis)

What is Sinusitis?

Sinuses are air pockets or cavities that are lined with a thin mucous membrane, the same as the lining of the nose. There are four pairs in the head (maxillary, ethmoid, sphenoid and frontal) and their purpose is to control the temperature and humidity of the air reaching the lungs. The sinuses are connected to the nose through small openings called ostia.

There are two types of sinusitis – acute and chronic.

Acute sinusitis

Acute sinusitis causes severe but temporary symptoms which are usually experienced after a cold. A week or more after the symptoms of a cold begin, you will experience a green-yellow nasal discharge associated with pain around the cheeks, eyes and / or forehead. Patients may also experience swelling and a high fever as well as toothache.

Chronic sinusitis

Conversely, chronic sinusitis lasts for several weeks. It may be caused by an infection of the sinuses that does not resolve itself, or an allergy that affects the lining of the nose and sinuses. Common symptoms include:

  • Nasal obstruction
  • Nasal discharge
  • Headache
  • Low grade fever
  • Facial discomfort
  • Reduced sense of smell
  • Halitosis

What are the causes of Sinusitis?

The pain experienced with sinusitis is usually caused by a blockage of the sinus opening, which could be caused by infections, irritants, allergies or a structural abnormality.


Adults can suffer from a cold or upper respiratory tract infection up to three times a year, with children getting them more regularly. Following a cold, when mucus turns yellow or green as opposed to clear it is a sign of a bacterial infection, which, in addition to viral infection, can cause swelling of the lining of the nose and thickening of the normal mucus. Sinus infection may occur as a result of this as it inhibits proper sinus drainage.


Swelling of the lining of the nose can also be caused by irritants like air pollution, smoke and chemical irritants (e.g. some sprays containing pesticides), disinfectants and household detergents. Again, this can impair sinus drainage through narrowing or blocking the opening to the sinuses and in turn causing infection.


Allergies can cause inflammation inside the nose as common symptoms of an allergic reaction include nasal stuffiness, runny nose, sneezing and itchy watery eyes. Chronic sinusitis is sometimes associated with asthma and allergies are responsible for asthma in some patients. The nasal stuffiness experienced with allergies makes asthma more difficult to control.

Structural abnormality

Narrowing of the nasal cavity can sometimes be caused by structural problems as a result of trauma or developed when growing. If the narrowing is severe then it causes a blockage with mucus building up behind it and leading to infection.

How is Sinusitis diagnosed?

Your doctor will examine the nasal lining and the sinus openings using a nasal endoscope.

How is Sinusitis treated?

Acute sinusitis is treated with antibiotics and medication to reduce swelling in the lining of the nose, such as decongestants.

Chronic sinusitis may need longer term treatment such as antibiotics, decongestants and nasal steroid sprays. Antihistamines may be useful for patients with an allergy.

Most cases will be effectively managed by medical treatment, but in those that are not, surgery may be considered. A number of surgical options are available, most of which do not require making cuts to the skin surrounding the nose. Your consultant will discuss with you which is the most appropriate, depending on the severity of your symptoms, and may arrange a scan to assist with the decision. Your scans will be carried out at our dedicated imaging and diagnostics centre.

Sinus infection (Sinusitis) Specialists

All our private ENT specialists at OneWelbeck in London are leaders in their sub-specialties, providing the highest quality treatment to ensure you receive the best available care. Click on the profiles below to see which of our consultants specialist in sinusitis.

Contact Us

To speak with a specialist about Rhino-sinusitis contact our team today.
We are available from Monday to Friday: 8am – 8pm.