• Clinical science

Acute tonsillitis


Acute tonsillitis is an inflammation of the pharyngeal tonsils that frequently arises 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 a sudden onset of fever, sore throat, and painful swallowing. Tender, swollen cervical lymph nodes and tonsillar exudates may occur. Normally, the disease is self-limiting. However, if group A streptococcal infection is confirmed with rapid antigen detection test and/or throat culture, treatment with antibiotics (penicillin) should be initiated to prevent rheumatic fever and poststreptococcal glomerulonephritis. 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 < 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]


Acute tonsillitis is primarily a clinical diagnosis that may be supported by blood tests and confirmed via microbiological testing.

  • Modified Centor score[5]: a set of criteria that is used to estimate the probability that pharyngitis is caused by group A Streptococcus (GAS).
    • Criteria
      • No cough (1 point)
      • Anterior cervical adenopathy (1 point)
      • Fever (1 point)
      • Tonsillar exudates or swelling (1 point)
      • Age:
        • 3–14 years (1 point)
        • 15–44 years (0 point)
        • ≥ 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
      • Score ≥ 4: empiric antibiotics
  • Microbiologic testing [6]
    • Confirmatory tests: rapid antigen detection test and/or throat culture
      • Rapid GAS antigen detection test
        • Throat swab allows simple and quick detection of group A streptococcal infection (highly specific, sensitivity ∼70–90%)[5]
        • A negative test should be confirmed by throat culture in children and adolescents.
      • Throat culture: to identify pathogen and determine antibiotic sensitivity [7]
  • Blood tests

Differential diagnoses

Aphthous stomatitis
  • Unknown
  • Ulcers on anterior oral mucosa
  • Usually no systemic symptoms
  • Herpes-like oral lesions: multiple 1-mm vesicles located on the posterior oropharynx and tonsils; pharyngeal and tonsillar redness
  • Fibrin-covered ulcerations appear in later stages
  • Sore throat and high fever
  • May occur as a component of the hand, foot, and mouth disease
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's 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 (diphtheric croup)
  • Pseudomembranes
  • Inflammation often exceeds the tonsils, mucosal bleeding
Agranulocytic angina

The differential diagnoses listed here are not exhaustive.


Acute tonsillitis is usually self-limiting (symptoms usually resolve within 3–4 days without treatment). However, antibiotic therapy is indicated for bacterial infections.[10]


A maculopapular rash may result from mistakenly treating an EBV infection (infectious mononucleosis) with ampicillin!


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



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