• Clinical science

Acute tonsillitis


Acute tonsillitis is an inflammation of the tonsils that frequently occurs in combination with an inflammation of the pharynx (tonsillopharyngitis). It is particularly common in children and young adults and is primarily caused by viruses and group A streptococci (GAS). Acute tonsillitis is characterized by the sudden onset of fever, sore throat, and painful swallowing. Tender, swollen cervical lymph nodes and tonsillar exudates may occur. The disease is normally self-limiting. However, if GAS infection is confirmed via rapid antigen detection test and/or throat culture, treatment with antibiotics (penicillin) should be started to prevent rheumatic fever. Tonsillectomy is an option in recurrent and chronic tonsillitis, although the procedure is associated with a high risk of postoperative bleeding. Peritonsillar abscess and parapharyngeal abscess are serious suppurative complications of acute bacterial tonsillitis and require immediate treatment.


  • Peak incidence
    • Viral tonsillitis: children < 5 years and young adults [1]
    • Streptococcal tonsillitis: children aged 5–15 years; rare in children aged < 2 years

Epidemiological data refers to the US, unless otherwise specified.


Clinical features

  • Sudden onset of symptoms
  • Red and swollen pharynx, tonsillar exudates [3]
  • Fever, sore throat, dysphagia
  • Painful, swollen cervical lymph nodes
  • Foul breath
  • If viral: headache, earache, nasal congestion, and cough [3]

Trismus and changes in voice quality indicate the formation of potentially life-threatening peritonsillar abscess! [4]


Diagnosis ; of acute tonsillitis is primarily clinical but may be further supported by blood tests and confirmed via microbiological testing.

Modified Centor score [5]

A set of criteria used to estimate the probability that pharyngitis is caused by GAS

  • Criteria
    • No cough (1 point)
    • Tender anterior cervical adenopathy (1 point)
    • Fever (1 point)
    • Tonsillar exudates or swelling (1 point)
    • Age
      • 3–14 years (1 point)
      • 15–44 years (0 points)
      • ≥ 45 years (-1 point)
  • Approach
    • Score ≤ 1: no further diagnostic testing or antibiotic treatment is indicated
    • Score 2 or 3: rapid antigen detection testing (RADT) and/or throat culture is indicated
    • Score ≥ 4: empiric antibiotics

Think of M-CENTOR to remember the Modified Centor score criteria: M = Must be older than 3 years, C = Cough absent, E = Exudate on the tonsils, N = Node enlargement, T = Temperature elevation, OR = young OR old.

Microbiological testing [6]

  • Confirmatory tests: rapid antigen detection test and/or throat culture
    • Rapid GAS antigen detection test
      • Throat swab allows for simple and quick detection of GAS infection (highly specific, sensitivity ∼ 70–90%). [5]
      • In children and adolescents, negative test results should be confirmed with throat culture.
    • Throat culture: to identify pathogen and determine antibiotic sensitivity [7]
  • Blood tests

Differential diagnoses

Disease Etiology Clinical features
  • See Etiology section above.
Aphthous stomatitis
  • Unknown
  • Ulcers on anterior oral mucosa
  • Usually no systemic symptoms
Herpetic pharyngotonsillitis/herpetic gingivostomatitis
  • Multiple small oral lesions located in the anterior oropharynx and lips
  • Fever, sore throat, pharyngeal redness
Vincent angina
  • Unilateral ulcers on the pharyngeal tonsils
  • Mild general symptoms
  • Difficulty swallowing
  • Foul breath
Ludwig angina
  • Submandibular space infection
  • Fever, mouth pain, stiff neck, difficulty swallowing, trismus
  • Airway obstruction may occur! [8]
Oral thrush (fungal tonsillitis)
  • Pseudomembranous stomatitis with white plaques
Pharyngeal syphilis
Tonsillitis in infectious mononucleosis
Tonsillitis in diphtheria (diphtheritic croup)
  • Pseudomembranes
  • Inflammation often exceeds the tonsils; mucosal bleeding
Agranulocytic angina

The differential diagnoses listed here are not exhaustive.


Acute tonsillitis is typically self-limiting (symptoms usually resolve within 3–4 days without treatment). However, antibiotics are indicated for bacterial infections. [11]


Mistakenly treating an EBV infection (infectious mononucleosis) with ampicillin can lead to maculopapular rash.


  • Indications
    • Recurrent and chronic tonsillitis
    • Extreme hypertrophy of the tonsils (“kissing tonsils”)
    • A history of peritonsillar abscess
    • Tonsillitis that does not respond to antibiotic treatment
    • Tonsillitis in children who meet all of the Paradise criteria except those regarding documentation (see table below)
Paradise criteria for tonsillectomy in children [14]
Criterion Description
Minimum frequency of sore throat episodes
  • ≥ 7 episodes in the past year, OR
  • ≥ 5 episodes/year in the past 2 years, OR
  • ≥ 3 episodes/year in the past 3 years
Clinical features
  • Each episode should be reflected in the medical documentation with the description of the clinical features mentioned above OR
  • There is subsequent observation by the physician of 2 episodes with patterns of frequency and clinical features consistent with the initial history.

NSAIDs (e.g., acetylsalicylic acid) are contraindicated for postoperative pain relief because of the increased risk of bleeding!


Streptococcus "ph"yogenes is the most common cause of bacterial pharyngitis, which can result in rheumatic "phever" and poststreptococcal glomerulonephritis.


We list the most important complications. The selection is not exhaustive.