Sinusitis refers to inflammation of the paranasal sinuses in the face. This is usually accompanied by inflammation of the nasal cavity and can be referred to as rhinosinusitis. It is very common.

Sinusitis can be:

  • Acute (less than 12 weeks)
  • Chronic (more than 12 weeks)


Basic Anatomy

The paranasal sinuses are hollow spaces within the bones of the face, arranged symmetrically around the nasal cavity. They produce mucous and drain into the nasal cavities via holes called ostia. Blockage of the ostia prevents drainage of the sinuses, resulting in sinusitis. 

There are four sets of paranasal sinuses:

  • Frontal sinuses (above the eyebrows)
  • Maxillary sinuses (either side of the nose below the eyes)
  • Ethmoid sinuses (in the ethmoid bone in the middle of the nasal cavity)
  • Sphenoid sinuses (in the sphenoid bone at the back of the nasal cavity)



Inflammation of the sinuses can be caused by:

  • Infection, particularly following viral upper respiratory tract infections
  • Allergies, such as hayfever (with allergic rhinitis)
  • Obstruction of drainage, for example, due to a foreign body, trauma or polyps
  • Smoking


Patients with asthma are more likely to suffer from sinusitis. 



The typical presentation of acute sinusitis is someone with a recent viral upper respiratory tract infection presenting with:

  • Nasal congestion
  • Nasal discharge
  • Facial pain or headache
  • Facial pressure
  • Facial swelling over the affected areas
  • Loss of smell


Examination may reveal:

  • Tenderness to palpation of the affected areas
  • Inflammation and oedema of the nasal mucosa
  • Discharge
  • Fever
  • Other signs of systemic infection (e.g., tachycardia)


Chronic sinusitis involves a similar presentation but with a duration of more than 12 weeks. Chronic sinusitis may be associated with nasal polyps, which are growths of the nasal mucosa.



In most cases, investigations are not necessary. In patients with persistent symptoms despite treatment, investigations include: 

  • Nasal endoscopy 
  • CT scan



This section is a brief outline based on the NICE clinical knowledge summaries (updated March 2021). Always check the full local and national guidelines when treating patients. 

Patients with systemic infection or sepsis require admission to hospital for emergency management. 

NICE recommend not offering antibiotics to patients with symptoms for up to 10 days. Most cases are caused by a viral infection and resolve within 2-3 weeks.

NICE recommend for patients with symptoms that are not improving after 10 days, the options of:

  • High dose steroid nasal spray for 14 days (e.g., mometasone 200 mcg twice daily)
  • A delayed antibiotic prescription, used if worsening or not improving within 7 days (phenoxymethylpenicillin first-line)


Options for chronic sinusitis are:

  • Saline nasal irrigation
  • Steroid nasal sprays or drops (e.g., mometasone or fluticasone)
  • Functional endoscopic sinus surgery (FESS)


Nasal Spray Technique

Steroid nasal sprays are often misused, which means they will not be as effective. A good question to ask is, “do you taste the spray at the back of your throat after using it?” Tasting the spray means it has gone past the nasal mucosa and will not be as effective. 

The technique involves:

  • Tilting the head slightly forward
  • Using the left hand to spray into the right nostril, and vice versa (this directs the spray slightly away from the septum)
  • NOT sniffing hard during the spray
  • Very gently inhaling through the nose after the spray


TOM TIP: It is worth learning and practising how to explain the use of a steroid nasal spray. You may be asked to explain how to use a steroid nasal spray in your OSCEs. I probably explain the technique several times a month in general practice. 


Functional Endoscopic Sinus Surgery

Functional endoscopic sinus surgery (FESS) involves using a small endoscope inserted through the nostrils and sinuses. Instruments are used to remove or correct any obstructions to the sinuses. Obstruction may be caused by swollen mucosa, bone, polyps or a deviated septum (surgery to correct a deviated septum is call septoplasty). Balloons may be inflated to dilate the opening of the sinuses.

Patients need a CT scan before the procedure to confirm the diagnosis and assess the structures.


Last updated July 2021