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 . Tonsillectomy is a treatment option for recurrent and chronic tonsillitis, especially in patients with tonsillar hypertrophy that causes obstructive sleep-disordered breathing. and are serious suppurative complications of acute bacterial tonsillitis and require immediate treatment.
- Peak incidence 
- Peak season: Acute GAS tonsillopharyngitis most commonly occurs in winter and spring. 
Epidemiological data refers to the US, unless otherwise specified.
- Viral (50–80% of cases): adenovirus, EBV, CMV, HSV, rhinovirus, coronavirus, influenza and parainfluenza viruses, HIV 
Bacterial (15–30% of cases)
- Most common: acute GAS tonsillopharyngitis caused by Streptococcus pyogenes, also known as Group A Streptococcus (GAS) 
- Others: Neisseria gonorrhoeae, Corynebacterium diphtheriae, Mycoplasma pneumonia, Fusobacterium necrophorum, Group C and Group G Streptococcus 
- Necrotizing (or anaerobic) tonsillopharyngitis (sometimes referred to as ): A rare anaerobic and/or mixed organism infection that may overlap with necrotizing periodontal disease. 
- Recurrent tonsillopharyngitis and chronic tonsillitis: polymicrobial infections with aerobic bacteria (typically streptococci, staphylococci, Haemophilus influenzae) and anaerobic bacteria
Acute bacterial tonsillopharyngitis 
- Sudden onset; of symptoms: fever, sore throat, dysphagia
- Significantly inflamed pharynx
- Cervical lymphadenitis
- Absence of cough
- can also present as with:
- Rarely, features of necrotizing infection and/or dental disorders and/or periodontal disease may be present (see “Vincent angina”). 
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. 
Acute viral tonsillopharyngitis 
Red flags for tonsillopharyngitis 
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 (e.g., , ), , , and rarely, sepsis. 
- Asymmetric tonsils
- Displaced uvula
- Unilateral facial swelling
- Muffled or “hot potato” voice
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. 
- Assess for clinical features of , , and .
- Proceed to immediate treatment if or are present.
Suspected : Consider diagnostic testing to identify and treat GAS infection and minimize its transmission and complications (e.g., acute rheumatic fever). 
- Consider deferring diagnostic testing based on a clinical scoring system, e.g., no testing if ≤ 1.
- Obtain a ≥ 3 years old
if indicated, e.g., symptomatic patient
- Positive GAS infection likely; proceed to treatment. :
- Negative : Obtain a throat culture in children (not routinely required in adults). 
Suspected : Diagnostic testing is not routinely recommended.
- Suspected : Start with . 
- Suspected COVID-19: See “ ” for details.
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. 
Testing for GAS infection is not recommended in patients with clinical features that strongly suggest . 
Rapid strep test 
- Modality: (RADT) specific for GAS antigens.
- Indications: first-line test in suspected acute bacterial tonsillopharyngitis
- Procedure: Swab the patient's tonsils and the back of the throat.
- Findings 
- Confirmatory test to definitively rule out GAS infection in symptomatic children and adolescents with a negative RADT
- Lack of clinical improvement after 3–4 days despite antibiotic treatment 
- Recurrent or chronic tonsillitis 
- Consider in adults with risk factors for invasive GAS infection. 
- Causative bacteria and their antibiotic susceptibility (see “Etiology” for details)
- Time to result: 24–48 hours
Clinical scoring systems 
- Rationale: Estimate the likelihood of acute bacterial pharyngitis based on clinical features alone.
- Example: the
- Identifying patients with a low likelihood of GAS infection, thereby minimizing unnecessary diagnostic tests and antibiotic therapy.
- The use of scoring systems to identify patients with a high likelihood of bacterial pharyngitis in order to treat empirically without testing is controversial. 
|Modified Centor score |
|> 44 years||-1|
|Exudate or swelling on tonsils||Yes||+1|
|Tender or swollen anterior cervical lymph nodes||Yes||+1|
|Temperature > 100.4°F (38°C)||Yes||+1|
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.
Additional laboratory tests
Not routinely indicated; can be obtained as supportive diagnostic evidence
- Inflammatory markers: CRP, ESR
- Antistreptolysin O (ASO) titer
- Not routinely indicated
- Consider CT of head and neck if there is clinical suspicion of suppurative complications
|Differential diagnoses of acute tonsillopharyngitis|
|(fungal tonsillitis)|| |
|Pharyngeal syphilis|| |
|Tonsillitis in (diphtheritic croup)|| |
|Agranulocytic angina|| |
The differential diagnoses listed here are not exhaustive.
Recommendations in this section are consistent with the 2012 IDSA and the 2009 AHA/AAP guidelines on GAS pharyngitis. 
- All patients
GAS pharyngitis and/or tonsillitis: typically self-limited; prescribe antibiotics to prevent complications (e.g., peritonsillar abscess, rheumatic fever) and decrease transmission 
- Positive or throat culture: Initiate .
- Negative : Wait for throat culture results; treat if culture positive. 
- Empiric treatment (e.g., for patients with ≥ 4) is controversial and not routinely recommended. 
- Advise isolation and ≥ 12 hours of antibiotic therapy.  until patients are afebrile and have received
- Acute viral tonsillopharyngitis: self-limited; continue supportive care and provide patient education.
Disposition: Outpatient treatment is possible for most patients.
- Improvement can be expected within 3–4 days. 
- Reasons to return to seek care: Persistent or worsening symptoms
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. 
Supportive care 
- Ensure adequate hydration.
- Consider household remedies such as salt-water gargles.
- Consider oral topical benzocaine lozenges, phenol throat sprays, compounded mouthwash.  : e.g.,
- Consider single low-dose corticosteroids to reduce symptom duration in patients > 3 years old. 
- Analgesics and antipyretics 
- Indication: patients with laboratory confirmation of GAS infection 
- 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”). 
|Recommended antibiotic regimens for acute GAS pharyngitis |
|No penicillin allergy|| |
Penicillin V : treatment of choice
|Benzathine penicillin G :||Single-dose|
|Penicillin allergy||Cephalexin||10 days|
|History of anaphylaxis to penicillin: clindamycin or macrolides||Clindamycin||10 days|
|Azithromycin ||5 days|
|Dosages described here are valid for adults and children ≥ 2 years old.|
- 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. 
- Extreme hypertrophy of the tonsils (“kissing tonsils”) causing . 
- Documented recurrent throat infections 
- Suspected tonsillar neoplasm
- Chronic tonsillitis
- Consider in patients with any of the following:
- Total tonsillectomy
- Subtotal tonsillectomy
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. 
- Intraoperative: injury to adjacent structures, e.g., the carotid artery
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. 
Posttonsillectomy hemorrhage 
- Background: The risk of bleeding increases with age, reaching up to 20% in adults. 
- Bleeding can range from clot formation and oozing to active profuse hemorrhage.
- may be present.
- Move patients to a monitored setting with airway and resuscitation equipment available.
- Examine the posterior pharynx for signs of recent and/or active bleeding.
- If any bleeding is visible (e.g., clots, oozing, or active hemorrhage), establish large-bore IV access and obtain CBC, coagulation panel, and .
- Consult ENT surgery early.
- Establish NPO status (at least until evaluated by ENT surgeon).
- Small bleed that has self-resolved: Consider observation under ENT for 12–24 hours. 
- 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 while urgently contacting the operating room and ENT for high-priority surgical intervention.
- If are present, initiate followed by .
- Diagnostic tests are not routinely required.
- Consider testing for COVID-19 or infectious mononucleosis as needed.
- Supportive care
- Provide symptomatic treatment, e.g., analgesia, antipyretics.
- Use a clinical scoring system (e.g., modified Centor score) to identify patients at low risk of GAS infection.
- Suspected acute GAS tonsillopharyngitis: Perform RADT.
- If RADT is negative: Obtain a throat culture in children and adolescents to reliably rule out GAS infection.
- If RADT and/or throat culture is positive: Initiate .
- Cervical lymphadenitis
- Infectious thrombophlebitis of the internal jugular vein (Lemierre syndrome): A severe, potentially fatal condition usually resulting from oropharyngeal infections
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.