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Acute tonsillitis and pharyngitis

Last updated: August 13, 2021

Summarytoggle arrow icon

Acute tonsillitis is an inflammation of the tonsils that frequently occurs in combination with an inflammation of the pharynx (tonsillopharyngitis). The terms tonsillitis and pharyngitis are often used interchangeably, but they refer to distinct sites of inflammation. Acute tonsillitis and pharyngitis are particularly common in children and young adults and are primarily caused by viruses or group A streptococci (GAS). They are characterized by the sudden onset of fever, sore throat, and painful swallowing. Patients may also have tender, swollen cervical lymph nodes and tonsillar exudates. The disease is normally self-limited. However, if GAS infection is confirmed via rapid antigen detection test and/or throat culture, treatment with antibiotics (most often penicillin) should be initiated to prevent rheumatic fever. Tonsillectomy is a treatment option for recurrent and chronic tonsillitis, especially in patients with tonsillar hypertrophy that causes obstructive sleep-disordered breathing. Peritonsillar abscess and parapharyngeal abscess are serious suppurative complications of acute bacterial tonsillitis and require immediate treatment.

Epidemiological data refers to the US, unless otherwise specified.

Trismus and change in voice quality indicate the formation of potentially life-threatening peritonsillar abscess!

Approach [2]

The diagnosis of acute tonsillitis or acute pharyngitis is primarily clinical.

Infectious mononucleosis (IM) can manifest with clinical features similar to acute bacterial tonsillopharyngitis. Consider a heterophile antibody test if clinical suspicion for IM is high.

The diagnostic workup of suspected acute bacterial tonsillopharyngitis is described below.

Clinical scoring systems

Modified Centor score [8][9]
Criteria Points
Age 3–14 years +1
15–44 years 0
> 44 years -1
Exudate or swelling on tonsils Yes +1
No 0
Tender or swollen anterior cervical lymph nodes Yes +1
No 0
Temperature > 100.4°F (38°C) Yes +1
No 0
Cough Absent +1
Present 0


  • Score ≤ 1: no further diagnostic testing needed
  • Score ≥ 2: Consider rapid antigen detection testing (RADT) and/or throat culture.
  • Score ≥ 4: Consider empiric antibiotic therapy (controversial) [2][10]

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.

Empiric antibiotic therapy for patients with a modified Centor score ≥ 4 is not routinely recommended. [2]

Rapid antigen detection test (RADT) [2]

Testing for GAS infection is not recommended in patients with clinical features that strongly suggest acute viral tonsillopharyngitis. [2]

Throat culture

  • Indications
  • Findings
    • Causative bacteria and their antibiotic susceptibility (see “Etiology” for details)
    • Time to result: 24–48 hours

Additional laboratory tests

Not routinely indicated; can be obtained as supportive diagnostic evidence

An elevated antistreptolysin O (ASO) titer indicates a previous GAS infection. ASO titer assay is not indicated in an acute setting but rather in the workup of nonsuppurative complications of GAS tonsillopharyngitis (e.g., acute rheumatic fever, poststreptococcal glomerulonephritis). [2]

Imaging [11]

  • Not routinely indicated
  • Consider CT of head and neck if there is clinical suspicion of suppurative complications
Differential diagnoses of acute tonsillopharyngitis
Disease Etiology Clinical features
Aphthous stomatitis
  • Unknown
Herpetic pharyngotonsillitis/herpetic gingivostomatitis
Vincent angina
Ludwig angina
Oral thrush (fungal tonsillitis)
Pharyngeal syphilis
Tonsillitis in infectious mononucleosis
Tonsillitis in diphtheria (diphtheritic croup)
Agranulocytic angina

The differential diagnoses listed here are not exhaustive.

Approach [2]

General measures [2]

Avoid aspirin in children due to the risk of Reye syndrome.

Antibiotic therapy [2]

  • Indication: patients with laboratory confirmation of GAS infection [2][10]
  • Important consideration: The antibiotic regimens described here are valid for children ≥ 2 years of age and for adults.
Recommended antibiotic regimens for acute GAS pharyngitis [2]
Drug Duration
No penicillin allergy

Penicillin V : treatment of choice

10 days
Amoxicillin 10 days
Benzathine penicillin G : Single-dose
Penicillin allergy Cephalexin 10 days
Cefadroxil 10 days
History of anaphylaxis to penicillin: clindamycin or macrolides Clindamycin 10 days
Azithromycin 5 days
Clarithromycin 10 days

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

Tonsillectomy [1][2]

Indications [1][2][18]

  • Extreme hypertrophy of the tonsils (“kissing tonsils”) causing obstructive sleep-disordered breathing. [19]
  • Documented recurrent throat infections [20]
    • In patients who fulfill all of the following criteria: [1][2][18]
      1. Frequency of throat infections
        • ≥ 7 episodes in the past year
        • OR ≥ 5 episodes/year in the past 2 years
        • OR ≥ 3 episodes/year in the past 3 years
      2. Each episode has ≥ 1 of the following features:
      3. Each episode has been documented in a medical record.
    • If the above criteria are not met, consider tonsillectomy in patients with any of the following:
  • Suspected tonsillar neoplasm
  • Chronic tonsillitis

Procedure [1][21][22]

  • Total tonsillectomy
    • Tonsils are removed with their surrounding capsule.
    • Dissection is lateral to the tonsil in the plane between the tonsillar capsule and pharyngeal muscles.
  • Subtotal tonsillectomy
    • Subtotal removal of tonsillar tissue, leaving a margin of tissue on the tonsillar capsule
    • Dissection is from medial to lateral in a stepwise approach to preserve the capsule.

Do not use acetylsalicylic acid for postoperative pain relief after tonsillectomy because of the increased risk of bleeding. Recommended analgesics after tonsillectomy are ibuprofen and acetaminophen. [1][23]

Complications [1]

  • Intraoperative: injury to adjacent structures e.g., the carotid artery
  • Postoperative: bleeding , referred otalgia, nasopharyngeal stenosis

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

References: [3][24]

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

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  13. Oliver J, Malliya Wadu E, Pierse N, Moreland NJ, Williamson DA, Baker MG. Group A Streptococcus pharyngitis and pharyngeal carriage: A meta-analysis. PLoS Negl Trop Dis. 2018; 12 (3): p.e0006335. doi: 10.1371/journal.pntd.0006335 . | Open in Read by QxMD
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  15. Chow AW. Submandibular space infections (Ludwig's angina). In: Post TW, ed. UpToDate. Waltham, MA: UpToDate. updated: July 31, 2015. Accessed: November 6, 2016.
  16. Evidence-Based Diagnosis and Management of ENT Emergencies. Updated: February 15, 2007. Accessed: May 6, 2019.
  17. Hicks CB, Clement M. Syphilis: Epidemiology, pathophysiology, and clinical manifestations in HIV-uninfected patients. In: Post TW, ed. UpToDate. Waltham, MA: UpToDate.§ionName=CLINICAL%20MANIFESTATIONS&anchor=H8#H8.Last updated: August 1, 2016. Accessed: November 6, 2016.
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  24. Krishna S, Hughes LF, Lin SY. Postoperative Hemorrhage With Nonsteroidal Anti-inflammatory Drug Use After Tonsillectomy. Arch Otolaryngol Head Neck Surg. 2003; 129 (10): p.1086. doi: 10.1001/archotol.129.10.1086 . | Open in Read by QxMD
  25. Coelho MotaVera et al.. CHAPTER 54A - Rheumatic Fever. Churchille Livingstone : p. 1091-1113
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