Tonsillitis refers to the inflammation of the tonsils secondary to infection.

It is most frequently viral in origin, causing a self-limiting illness characterised by a sore throat and fevers. 

Group A beta-haemolytic streptococcus (GABHS) is the most common bacterial cause. 


Clinical features

Tonsillitis refers to the inflammation of the tonsils secondary to infection.


  • Fevers
  • Sore throat
  • Dysphagia
  • Malaise


  • Inflamed tonsils
  • White exudate on tonsils
  • Lymphadenopathy

Tonsilitis clinical features

Centor criteria

The Centor criteria is used to guide antibiotic use in those presenting with sore throat and tonsillitis. 

Evaluate the patient for the following:

  • Tonsillar exudate
  • Tender anterior cervical lymphadenopathy or lymphadenitis 
  • History of fever (over 38°C)
  • Absence of cough

Each is worth one point, the higher the score the greater the chance the illness is caused by GABHS. 


Management depends on the severity of the tonsillitis and any underlying conditions that may impact the conditions clinical course.

Simple tonsillitis

A common cause of presentation in primary care. Most patients can be managed with antipyretic analgesia.

Those with a Centor score of 0-2 should not routinely be offered antibiotics. Those with a score of 3-4 may be offered antibiotics though the evidence shows minimal overall benefit from antibiotics. 

Many offer a ‘back-up’ prescription that can be used if symptoms persist for longer than 3-5 days. Phenoxymethylpenicillin is the first-choice antibiotic, clarithromycin or erythromycin may be used in those with penicillin allergy. Consider a lower threshold for antibiotics in patients at increased risk of rheumatic fever.

Severe tonsillitis

Symptoms may be severe with dysphagia and high fevers. Some patients benefit from IV fluid, antibiotics and a dose of IV steroids. If severe they may be admitted overnight for observation and reassessed after 12-24 hours of IV therapy. 

Note: In patients presenting with any of a severe sore throat, drooling, stridor or trismus – epiglottitis – a rare but potentially life-threatening condition should be considered. 

Special cases

Additional care is required in certain patient groups at increased risk of severe infections.

  • At risk of agranulocytosis (e.g. taking carbimazole): hold medication, send FBC and seek specialist advice.
  • Immunosuppressed patients: may be due to an illness (e.g. haematological malignancy, HIV/AIDS) or due to medications (e.g. chemotherapy, immunosuppressants post-transplant). Complete a clinical review and seek specialist advice.


Complications are rare but may be seen in bacterial tonsillitis. 

Rarely GABHS is associated with complications, these may be suppurative or non-suppurative.

Tonsillitis complications


  • Quinsy (peri-tonsillar abscess)
  • Acute sinusitis
  • Acute otitis media


  • Acute rheumatic fever
  • Acute glomerulonephritis


The NHS sets specific criteria that must be met for tonsillectomy to be considered.

NHS England fund tonsillectomies where:

  • Malignancy is suspected
  • More than one episode of quinsy or airway obstruction
  • Recurrent sore throat (seven or more eligible episodes in the last year or five or more in each of the last two years)

Note: Eligible episodes must score 3 or 4 in the Centor criteria.

Additionally, in children tonsillectomy (+/- adenoidectomy) may be considered where:

  • Failure to thrive
  • Sleep apnoea 
  • Significant impact on quality of life

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