Acute rhinosinusitis



Acute rhinosinusitis refers to acute inflammation of the nose and paranasal sinuses.

Acute rhinosinusitis is a common condition that is usually caused by a viral pathogen. It leads to typical features of nasal congestion, nasal discharge, and facial pressure/pain that is worse on bending forward. These symptoms completely resolve within 4 weeks. Similar to an upper respiratory tract infection, symptoms will improve without intervention and antibiotics are rarely required.


Rhinosinusitis is a better term than simply ‘sinusitis’ because inflammation of the nasal cavities almost always accompanies sinusitis.

Sinusitis versus rhinosinusitis

  • Sinusitis: symptomatic inflammation of the paranasal sinuses
  • Rhinosinusitis: symptomatic inflammation of the nasal cavities and paranasal sinuses

The term ‘rhinosinusitis’ is preferred to sinusitis because inflammation of the sinuses seldom occurs without inflammation of the nasal cavities. However, the two terms should be regarded as synonymous.

Acute versus chronic

  • Acute rhinosinusitis: symptoms persist for less than 4 weeks
  • Subacute rhinosinusitis: symptoms persist for up to 12 weeks
  • Chronic rhinosinusitis: symptoms last more than 12 weeks

In addition, if patients develop ≥4 episodes of acute rhinosinusitis within a year with resolution of symptoms between episodes, this is referred to as ‘acute recurrent rhinosinusitis’.

Uncomplicated versus complicated

  • Uncomplicated rhinosinusitis: inflammation that does not extend beyond the anatomical boundaries of the nasal cavities and paranasal sinuses
  • Complicated rhinosinusitis: evidence of clinical extension of inflammation outside the nasal cavity and paranasal sinuses (e.g. orbital cellulitis, osteomyelitis, meningitis)

Complicated rhinosinusitis is rare and seen in bacterial cases. It can be thought of as orbital or intracranial extension of the infection.


Acute rhinosinusitis is a common problem that can affect up to 1 in 7 patients per year.

In Europe, 1-2 per 100 general practice consultations are due to acute rhinosinusitis. The incidence is higher in women and can affect all ages, although it most commonly occurs in the 5-7th decades. Major risk factors for developing acute rhinosinusitis include smoking, older age, air travel, deep sea diving, swimming and asthma.

Aetiology & pathophysiology

Acute rhinosinusitis is most commonly due to an upper respiratory tract viral pathogen.

Acute rhinosinuitis is most commonly caused by viruses, although a small percentage (0.5-2%) are due to bacterial infections.


Direct contact between an infective viral pathogen and the nasal or conjunctival mucosa can lead to viral replication and symptoms within the first day of inoculation. It is suspected that nose blowing then prompts propagation of the infection to the paranasal sinuses. As the infection develops it leads to excess sinonasal secretions, increased vascular permeability and mucosal oedema.

Typical infective viral pathogens:

  • Rhinovirus
  • Parainfluenza virus
  • Influenza virus


Bacterial rhinosinusitis usually occurs as a secondary infection in an already inflamed sinus cavity. Thus, it can be thought about as one of the complications of viral rhinosinusitis. It can also occur secondary to any condition that effects drainage of the sinonasal passages (e.g. foreign body, cystic fibrosis) or impaired local immune responses (e.g. dental abscess).

Typical bacterial organisms include (in order of frequency):

  • Streptococcus pneumoniae
  • Haemophilus influenzae
  • Moraxella catarrhalis
  • Staphylococcus aureus
  • Group A streptococcus

Clinical features

The hallmark features of acute rhinosinusitis are nasal congestion, nasal discharge, and facial pressure/pain.

Typical clinical features of acute rhinosinusitis are nasal discharge, congestion and facial pressure/pain. Symptoms usually resolve, or at least partially resolve, within 7-10 days.

Features that may suggest a bacterial infection include symptoms >10 days, severe local pain, fever >38º, predominant unilateral symptoms, or ‘double worsening’. ‘Double worsening or sickening’ describes worsening symptoms after an initial period of symptom resolution.


  • Nasal discharge: usually purulent and copious
  • Nasal congestion
  • Facial fullness or congestion
  • Facial pain or pressure: typically worse with pressure over the sinuses and when bending forward
  • Reduced or loss of smell
  • Ear pain: often due to eustachian tube dysfunction due to obstruction
  • Fever
  • Headache
  • Halitosis
  • Dental pain
  • Fatigue


Physical signs may be limited, but typically focus around the cheekbone (i.e. zygomatic arch) that is in close approximation to the maxillary sinuses.

  • Erythema or swelling around the maxillofacial area
  • Tenderness over the zygomatic arch or maxillary sinus
  • Pain on percussion or palpation over the upper teeth

Diagnosis & investigations

The diagnosis of acute rhinosinusitis is clinical based on typical signs and symptoms.

A diagnosis of acute rhinosinusitis should be suspected in patients with acute onset (< 4 weeks) purulent nasal discharge with nasal congestion and/or facial pressure/pain. Additional clinical features (e.g. reduce sense of smell, headache) can be supportive of the diagnosis.

Features that support a bacterial over a viral infection include:

  • Persistent clinical features with no improvement (>10 days)
  • ‘Double worsening’: deterioration after a period of recovery
  • Persistent severe symptoms (e.g. fever >39º, severe facial pain): min. 3-4 consecutive days

Red flag features

These refer to clinical features that suggest complicated rhinosinusitis warranting urgent investigation in secondary care.

  • Severe, persistent headache
  • Periorbital oedema
  • Visual changes (e.g. reduce acuity, double vision)
  • Abnormal extra-ocular eye movements
  • Cranial nerve palsies
  • Proptosis
  • Pain on eye movement
  • Altered mental status
  • Meningism: headache, neck stiffness, photophobia


Routine investigations are not required for uncomplicated acute rhinosinusitis. In patients with suspected complicated infections, the following investigations may be useful:

  • Cultures: nasal, sputum, sinus, blood
  • Bloods: FBC, U&E, LFT, Bone, CRP
  • Facial and head imaging (e.g. CT, MRI)

Differential diagnosis

Clinical features often overlap with those of an upper respiratory tract infection (URTI). In URTI, facial pain is uncommon and patients often have a sore throat and cough.


The majority of cases of acute rhinosinusitis will resolve spontaneously and only require supportive care.

In general, supportive measures can be given to patients although no treatment has been proven to shorten the duration of the illness. Most patients should be reassured that symptoms will improve spontaneously and simple supportive measures such as analgesia (e.g. paracetamol) can be advised. Patients with a persistent illness that does not improve (>10 days) should be treated as presumed bacterial infection.

Supportive measures

  • Anti-pyretics (e.g. paracetamol)
  • Analgesia (e.g. paracetamol, ibuprofen)
  • Saline irrigation: prepare with sterile or bottled water
  • Steam inhalation


Antibiotics should not be offered to patients with uncomplicated acute rhinosinusitis with symptoms < 10 days. If symptoms persist for longer than ten days, short-term high-dose intranasal glucocorticoids can be considered or a delayed antibiotic prescription.

In patients with clear acute bacterial rhinosinusitis, oral antibiotics are the treatment of choice. Options include:

  • Phenoxymethylpenicillin (1st line)
  • Co-amoxiclav (if systemically unwell)
  • Doxycycline or clarithromycin (if penicillin allergy)

Pharmacological agents

A variety of medical therapies may be advised but the evidence for their use is limited. The most beneficial is probably short-term intranasal glucocorticoids.

  • Intranasal glucocorticoids (e.g. mometasone)
  • Oral decongestants (e.g. phenylephrine)
  • Nasal decongestants (e.g. oxymetazoline)
  • Antihistamines: due to secretion drying effect


Patients with any red flag features should be referred urgently to secondary care for assessment of suspected complicated rhinosinusitis. Occasionally, patients who develop acute rhinosinusitis may need referral to ENT if they have recurrent episodes, failed treatment after antibiotics, resistant organisms, anatomical obstruction, or they are immunocompromised.


Complications are rare but can occur in patients with bacterial rhinosinusitis.

Complicated rhinosinusitis refers to extension of the infection beyond the nasal cavities and paranasal sinuses. This extension can lead to significant complications that require urgent hospital admission for treatment.

Major complications include:

  • Periorbital cellulitis
  • Orbital cellulitis
  • Subperiosteal abscess
  • Osteomyelitis
  • Intracranial abscess
  • Meningitis
  • Cavernous sinus thrombosis
  • Cranial nerve palsy

Last updated: February 2023
Author The Pulsenotes Team A dedicated team of UK doctors who want to make learning medicine beautifully simple.

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