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Tonsillitis is an acute inflammation of the tonsils, usually secondary to an infect. It is a common cause of sore throat, and a common reason for presentation to General Practice, and the Emergency Department.

Most cases are mild and self limiting, and will last less than 7 days.

More severe cases can result in inability to swallow and subsequent dehydration, and can require IV antibiotics, steroids and fluids.

Epidemiology and Aetiology

  • 70% viral
  • 30% bacterial
  • 90% will recover within a week without treatment
  • Common in children age 5-10 and young adults age 15-25
  • Bacterial tonsillitis is most commonly cause by Group A streptococcus (aka “Strep Throat”). This is carried in normal healthy throats in the general population. Rates of carriage decline with age, from about 10% of under 14’s to <1% of over 45s.

Presentation and diagnosis

Sore throat!
Use the Centor Criteria to help decide if antibiotics are necessary. There is a 50% chance of the tonsillitis having a bacterial cause if:

  • Pus on tonsils (tonsilar exudate)
  • Pyrexia (temperature >38 degrees celsius)
  • No cough
  • Tender cervical lymph nodes

Antibiotics are recommended only for those scoring 4, or sometimes 3.

Pus on Tonsils as seen in tonsillitis
Pus on Tonsils as seen in tonsillitis


Investigations aren’t usually necessary. You can to throat swabs for Group A beta-haemolytic streptococcus but this is an unpleasant procedure, results take several days, and often an individual can be a carrier without this being the cause of their tonsillitis. It is also unlikely to alter management, especially if you are using the censor criteria, as above.
Some advocate the use of rapid antigen testing from a throat swab, as this only takes a few minutes, but the evidence shows that it does not alter prescribing patterns, and so is probably not useful.


  • Mostly supportive – paracetamol and ibuprofen
  • Avoid giving antibiotics unless four features above are present or if systemically unwell
  • Avoid amoxicillin – as this causes a rash if the patient has glandular fever.
  • Penicillin V (aka phenoxymethypenicillin) is typically used if they meet the criteria. A typical adult dose is 500mg QID
    • Erythromycin is a suitable alternative if the patient is penicillin allergic.
  • Systemically unwell
    • IV Benzylpenicillin 1g stat
    • Steroids – e.g. IV dexamethasone 10mg – aiming to reduce tonsillar swelling
    • IV fluids
    • Check for peritonsillar abscess (see below)

Complications of Tonsillitis

  • Ear pain – not always due to otitis media – can just be referred pain
  • Otitis media – particularly in children
  • Inability to swallow and resultant dehydration
  • Quinsy – this is a peritonsillar abscess. Patients may have:
    • Assymetrical throat swelling
    • Severe throat pain / pain out of proportion with other clinical signs
    • Systemically unwell
Peritonsillar Abscess
Peritonsillar Abscess


  • Common cold – the common cold will cause similar features and in general practice a lot of patient may request or expect antibiotics. Use the Centor Criteria to decide and to justify your decision.
  • Glandular fever – Epstein Barr Virusaka infectious mononucleosis – typically presents in adolescents or young adults, but children can get it too. Rare in adults. Often accompanied by general malaise and tiredness. Can take several week to resolve, particularly the lethargy and treatment is only supportive.
    • Rarely, glandular fever can cause a ruptured spleen, or jaundice. Jaundice is usually mild and self-limiting, but the ruptured spleen can be life threatening. The spleen may become enlarged but is highly unlikely to rupture. You may want to ask patients to avoid contact sports or anything that puts them at risk of traumatic splenic injury.
    • In all instances of possible tonsillitis – AVOID AMOXICILLIN! If given glandular fever, amoxicillin can cause a nasty urticarial rash
  • Epiglottitis – be wary – will require immediate acute admission. Listen for stridor and look out for any increased work of breathing


In case of recurrent tonsillitis, tonsillectomy can be considered.

Tonsillectomy is less common than in past decades, but still routinely performed by ENT surgeons. The tonsils are important lymph nodes that help to fight infection of the upper respiratory tract, and are not ‘useless’ but in most people, can be safely removed.
Surgery is only used in recurrent cases of infection. The goal of surgery is to reduce the frequency of these infections.
There are strict NICE guidelines which stipulate tonsils can only be considered for removal if all four of the following conditions are met:

  • >5 episode tonsillitis in one calendar year
  • Symptoms ongoing for >1 year
  • Episodes are disabling and prevent normal function
  • Tonsillitis is known to be the cause of the sore throats!

Surgery is usually straightforward, but there is a risk of large haemorrhage, which can often occur several hours or days later (be aware when on call covering ENT wards as a foundation doctor!)

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Dr Tom Leach

Dr Tom Leach MBChB DCH EMCert(ACEM) FRACGP currently works as a GP and an Emergency Department CMO in Australia. He is also a Clinical Associate Lecturer at the Australian National University, and is studying for a Masters of Sports Medicine at the University of Queensland. After graduating from his medical degree at the University of Manchester in 2011, Tom completed his Foundation Training at Bolton Royal Hospital, before moving to Australia in 2013. He started almostadoctor whilst a third year medical student in 2009. Read full bio

This Post Has One Comment

  1. Osama Farooq

    Brilliant set of notes so simple and to the point thanks man may God bless you with good in life

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