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Tonsillitis refers to the inflammation of the tonsils in the throat. Tonsillitis may either be acute or chronic. A general practitioner (GP) typically sees around 120 people in a 2,000-patient population with an acute sore throat every year.Often presenting first as a sore throat to GPs, chronic tonsillitis generally has an incidence of 100 per 1,000-patient population in the UK.Among these patients, children and young adults, aged 5 to 24 years old, have the highest incidence, representing 50% of total cases.Annually, there are approximately 37,000 childhood tonsillectomy operations in the UK, costing the NHS approximately £42 million.4,5

Anatomy of the Oral Cavity

The tonsils are part of the ring-shaped lymphoid tissue in the oropharynx, known as Waldeyer’s ring. Waldeyer’s ring consists of four main groups of tonsils: adenoid, tubal, palatine and lingual. In clinical practice, tonsillitis usually refers to the inflammation of the palatine tonsils, which are located in the lateral walls of the oropharynx.6 Irrespective of size, the palatine tonsils should be visible on examination, unlike the others.

tonsils anatomy
Figure 1. Adenoid and palatine tonsils.11

Causes of Tonsillitis

Tonsillitis may be acute or chronic (repeated acute infections). An episode of acute tonsillitis can be caused by either a viral (more common) or bacterial infection.7 There are also non-infectious causes of tonsillitis.

Common viral causes include: 8

  • Rhinovirus (most common)
  • Coronavirus
  • Parainfluenza
  • Epstein Barr Virus (EBV)

Common bacterial causes include:

  • Group A beta-haemolytic Streptococcus (GABHS; most common)
  • Haemophilus influenzae
  • Moraxella catarrhalis

Non-infectious causes include:

  • Gastro-oesophageal reflux disease
  • Physical irritation (e.g. from nasogastric tubes)

History and Examination



Ask questions relating to symptoms outlined in CENTOR and FeverPAIN criteria (Tables 2 & 3).

Most common symptoms include:

  • Sore throat
  • Cough
  • Coryzal prodrome
  • Dysphonia
  • Pyrexia
  • Pain and malaise

Less common symptoms include:

  • Dysphagia
  • Halitosis


  • Measure vital signs – temperature might be raised (>38°C), blood pressure and heart rate may be abnormal secondary to dehydration (sore throats can result in reduced fluid intake)
  • Examine the patient’s throat and neck. See the Geeky Medics guide for examination of the oral cavity here.
  • Provide a chaperone if requested

Most common clinical findings:

  • Fever
  • Swollen, erythematous palatine tonsils
  • Cervical lymphadenopathy
  • Tonsils covered with exudate

Less common clinical findings:

  • Peritonsillar abscess (usually a complication of acute tonsillitis) – unilateral bulge above tonsils, accompanied by symptoms such as a sore throat, dysphagia, trismus and a classical hot potato voice

Differential Diagnoses

The clinical presentation of tonsillitis may mimic several other conditions. The key differentiating features between these diagnoses are presented in Table 1.

Table 1. Differential diagnoses of tonsillitis, and their distinguishing features

Differential diagnosis Features differentiating from tonsillitis
  • Acute and severe onset
  • Muffled voice
  • Drooling
  • Stridor
Infection mononucleosis (glandular fever) due to Epstein Barr Virus 
  • Pharyngitis of longer duration
  • Splenomegaly
  • FBC – raised WBC count with lymphocytosis
  • Positive Monospot test (in patients > 4 years old)
Squamous cell carcinoma
  • Unilateral tonsillar enlargement
  • Dysphonia
  • Ulcers


An acute episode of tonsillitis is traditionally diagnosed using clinical features alone. During this process, it is key for clinicians to identify whether tonsillitis is of viral or bacterial aetiology. This will allow for the appropriate prescription of antibiotics. This may be done with the help of the CENTOR (Table 1) and FeverPAIN criteria (Table 2).


Table 2. CENTOR criteria, indicating the likelihood of a bacterial (GABHS) tonsillitis. Scores are totalled from 0-49

CENTOR Criteria
Symptoms of tonsillitis Points
Tonsillar exudate 1
Tender anterior cervical lymphadenopathy 1
History of fever (>38°C) 1
Absence of cough 1
Total points 4


  • A score of 0-2 has a low probability of a GABHS infection and should be managed conservatively.
  • A score of 3-4 has a higher probability of a GABHS infection and should be treated with an antibiotic prescription.


Table 3. The FeverPAIN criteria consist of five symptoms of acute tonsillitis, each scoring 1 point, indicating the likelihood of a bacterial (GABHS) tonsillitis, scoring 0-5.9

FeverPAIN criteria
Symptoms of tonsillitis Points
Fever (during previous 24 hours) 1
Purulence (pus on tonsils) 1
Attend rapidly (within 3 days after symptoms’ onset) 1
Severely inflamed tonsils 1
No cough or coryza (inflammation of mucous membranes in the nose) 1
Total points 5


  • A score of 0-1 indicates a low possibility of GABHS infection and should be managed conservatively.
  • A score of 2-3 indicates a moderate possibility of GABHS infection. These patients can be either managed conservatively or given a delayed antibiotic prescription to use if symptoms do not resolve within three to five days or if they deteriorate.
  • A score of 4-5 suggests a high possibility of GABHS infection and should be managed with antibiotics.

Laboratory Investigations

Laboratory testing is not routinely performed as tests have no role in the diagnosis or management of tonsillitis. However, lab investigations may be useful in confirming a history of GABHS infection in patients with other conditions linked to GABHS, such as rheumatic fever and heart disease.

Examples of such investigations include:

  • Throat swab for culture (to detect the presence of bacteria)
  • Rapid streptococcal antigen test (to identify the presence of GABHS)
  • Monospot test for EBV
throat swab
Figure 2. Demonstration of a throat swab procedure.12


The overall management of tonsillitis can be broken down into acute and chronic management.

Acute Management

  • Supportive: hydration, fluids, ibuprofen ± paracetamol and rest
  • Prescribe antibiotics (if suspected bacterial infection):
    • Phenoxymethylpenicillin (Penicillin V) for 10 days.
    • If allergic to penicillin, clarithromycin or erythromycin for 5 days. Consult your local BNF for appropriate doses.
  • It is important to note that amoxicillin should be avoided as it can cause a generalised rash in patients who have EBV.

Chronic Management

NICE advises that certain patients with recurrent episodes of tonsillitis, who meet any of the following criteria,9 can be referred for tonsillectomy (surgical removal of the tonsillar glands8):

  • More than 7 documented, adequately treated, sore throat episodes in 1 year
  • More than 5 episodes in 2 years
  • More than 3 episodes in 3 years
  • For whom there is no other explanation for recurrent symptoms



There are multiple problems that can arise if tonsillitis is not appropriately identified and treated, including:

  • Otitis media (most common)
  • Sinusitis
  • Peritonsillar abscess (quinsy) – presents with difficulty swallowing, trismus (difficulty in opening the mouth due to spasm or pain), and airway compromise
  • Scarlet fever – caused by Streptococcus pyogenes (a form of GABHS), causing a rash on the chest or axillae following a sore throat and fever. Scarlet fever is traditionally known for its’ ‘strawberry tongue’ sign (Figure 3).
strawberry tongue
Figure 3. ‘Strawberry tongue’ sign in a patient with scarlet fever.13


Tonsillar haemorrhage is an ENT emergency, requiring immediate from an ENT surgeon and anaesthetist.

  • Primary haemorrhage (within 24 hours)
  • Secondary haemorrhage (after 24 hours, usually 5-10 days post-operatively) – due to infection of the tonsillar fossa

Key Points

  • Tonsillitis refers to inflammation of the tonsillar glands, mainly the palatine tonsils.
  • It is usually caused by a viral infection.
  • Clinically, the CENTOR and FeverPAIN criteria can be used by clinicians to distinguish between a viral and bacterial source of infection.
  • Most common reported symptoms include sore throat, cough and a coryzal prodrome.
  • Most common examination findings include fever, swollen, erythematous palatine tonsils, cervical lymphadenopathy and tonsillar exudate.
  • Medical management includes pain relief if viral, and phenoxymethylpenicillin (Penicillin V) if bacterial (depending on patient allergies).
  • Complications of tonsillitis include otitis media, peritonsillar abscess and scarlet fever.


1. MeReC Bulletin. Managing sore throats. Published in 1999. [LINK]

2. Georgalas C.C., Tolley, N.S. and Narula, P.A. Tonsillitis. Published in 2014. [LINK]

3. Caserta, M.T. and Flores, A.R. Mandell, Douglas and Bennett’s principles and practice of infectious diseases. Published in 2010. [LINK]

4. Baugh RF, Archer SM, Mitchell RB, et al. Clinical practice guideline: tonsillectomy in children. Published in 2011. [LINK]

5. NHS England, Monitor. 2016/17 National tariff payment system – Annex A: 2016/17 national prices and national tariff workbook. Published in 2016. [LINK]

6. Color Atlas of Oral and Maxillofacial Diseases – Bacterial Infections. Published in 2019. [LINK]

7. New England Journal of Medicine (NEJM) Acute pharyngitis. Published in 2001. [LINK]

8. Oxford Handbook of Clinical Specialties 10th Ear, Nose and Throat. Published in 2016. [LINK]

9. National Institute for Health and Care Excellence (NICE). Sore throat – acute. Published in 2018. [LINK]

10. British Medical Journal (BMJ) Best Practice. Tonsillitis. Published in 2019. [[LINK]]


11. Bruce Blaus. Tonsils&Adenoids. [CC BY-SA] [LINK]

12. Bruce Blaus. Throat Culture. [CC BY-SA] [LINK]

13. Lewis Fischer. Diseases of Infancy and Childhood. [CC BY-SA][LINK]


Miss Shadaba Ahmed

Consultant ENT Surgeon


Hannah Thomas

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