Acute tonsillitis and pharyngitis

Last updated: September 11, 2023

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.

Epidemiologytoggle arrow icon

Epidemiological data refers to the US, unless otherwise specified.

Etiologytoggle arrow icon

Clinical featurestoggle arrow icon

Acute bacterial tonsillopharyngitis [2]

Children < 3 years of age rarely develop GAS pharyngitis; GAS infection in this age group more typically manifests with fever, lymphadenopathy, mucopurulent rhinitis, and excoriated skin around the nostrils. [2]

Acute viral tonsillopharyngitis [2][3]

Red flags for tonsillopharyngitis [9]

The presence of any of the red flag features listed below may indicate suppurative and/or invasive complications of acute tonsillitis and/or pharyngitis, such as deep neck infections (e.g., peritonsillar abscess, retropharyngeal abscess), cervical lymphadenitis, mastoiditis, and rarely, sepsis. [2]

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

Diagnosticstoggle arrow icon

Recommendations in this section are consistent with the 2012 Infectious Disease Society of America (IDSA) and the 2009 American Heart Association (AHA)/American Academy of Pediatrics (AAP) guidelines on GAS pharyngitis. [2][10][11][12]

Approach [2][13]

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

Routine testing for GAS is not recommended for children < 3 years old, as their prevalence of GAS pharyngitis and risk of developing subsequent acute rheumatic fever are both low. Consider testing only if specific risk factors (e.g., close household contact) are present. [2][13]

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

Rapid strep test [2]

Throat culture

  • Indications
  • Findings [2]
    • Causative bacteria and their antibiotic susceptibility (see “Etiology” for details)
    • Time to result: 24–48 hours

Clinical scoring systems [2][14]

Modified Centor score [17][18][19]
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


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]

Additional laboratory tests

Not routinely indicated; can be obtained as supportive diagnostic evidence

Imaging [9]

  • Not routinely indicated
  • Consider CT of head and neck if there is clinical suspicion of suppurative complications

Differential diagnosestoggle arrow icon

Differential diagnoses of acute tonsillopharyngitis
Disease Etiology Clinical features
Aphthous stomatitis
  • Unknown
Herpetic pharyngotonsillitis/herpetic gingivostomatitis

Vincent angina (Acute necrotizing ulcerative gingivitis; ANUG) [5][6][7][8]

Ludwig angina
Oral thrush (fungal tonsillitis)
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.

Treatmenttoggle arrow icon

Recommendations in this section are consistent with the 2012 IDSA and the 2009 AHA/AAP guidelines on GAS pharyngitis. [2][10][11][12]

Approach [2][13]

Amoxicillin therapy in patients with infectious mononucleosis can trigger a maculopapular and/or morbilliform rash. Reserve antibiotics for patients with confirmed bacterial tonsillopharyngitis (e.g., positive rapid strep test or throat culture), whenever possible. [25]

Supportive care [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]
  • Suspected anaerobic or necrotizing infection (e.g., features of infection with fusobacterium or mixed organisms): Consult a specialist (e.g., ENT or infectious disease) for targeted therapy. (see also “Deep neck infections”). [5]
Recommended antibiotic regimens for acute GAS pharyngitis [2]
Drug Dosages described here are valid for adults and children ≥ 2 years old. Consult a pharmacist for dosing children < 2 years old. 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 [30] 5 days
Clarithromycin 10 days

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

Tonsillectomytoggle arrow icon


  • Ambulatory tonsillectomy is one of the most frequently performed procedures in children < 15 years of age.
  • In 2010, there were almost 300,000 cases in the US. [1][2]

Indications [1][2][31]

Procedure [1][34][35]

  • Total tonsillectomy
  • 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.

Admit children < 3 years of age and those with severe obstructive sleep apnea, obesity, or complex medical histories (e.g., Down syndrome, congenital heart disease, neuromuscular disease) for overnight monitoring after tonsillectomy. [1]

Complications [1]

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][37]

Posttonsillectomy hemorrhage [38][39]

  • Background: The risk of bleeding increases with age, reaching up to 20% in adults. [40][41]
  • Clinical features
  • Initial management
  • Minor bleeding
    • Small bleed that has self-resolved: Consider observation under ENT for 12–24 hours. [38]
    • History of recurrent bleeding or visualization of oozing or clot
      • Keep for observation with frequent clinical reassessment.
      • Definitive management as guided by ENT (e.g., cauterization at the bedside or in the operating room).
  • Active hemorrhage or history of severe hemorrhage: Evaluate and manage patients simultaneously using the ABCDE approach while urgently contacting the operating room and ENT for high-priority surgical intervention.

Secondary posttonsillectomy hemorrhage typically presents ∼ 1 week after surgery, around the time the eschar (fibrin clot) detaches. [43]

Acute management checklisttoggle arrow icon

Suspected acute viral tonsillopharyngitis

Suspected acute bacterial tonsillopharyngitis

Complicationstoggle arrow icon

Suppurative complications

Nonsuppurative complications

Antibiotic therapy for GAS pharyngitis can decrease the risk of rheumatic fever but does not affect the risk of PSGN. [2]

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

References: [3][44]

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

Referencestoggle arrow icon

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