Peritonsillar Abscess

A peritonsillar abscess, commonly known as quinsy, is one of the most serious complications of acute tonsillitis and represents the most frequent deep neck infection in adults. This condition occurs when pus collects in the space between the tonsil and the pharyngeal muscles, forming a painful abscess that can significantly impair swallowing, speaking, and even breathing. Affecting approximately 30 per 100,000 people annually in the United States, peritonsillar abscess typically occurs in adolescents and young adults, with peak incidence between ages 20-40. Without prompt treatment, this condition can lead to life-threatening complications, making early recognition and intervention crucial.

Medical Disclaimer: This information is for educational purposes only and should not replace professional medical advice. Always consult with a qualified healthcare provider for diagnosis and treatment of medical conditions.

Overview

Peritonsillar abscess develops when infection spreads beyond the tonsil capsule into the potential space between the tonsil and the superior constrictor muscle of the pharynx. This space, normally virtual, becomes filled with purulent material as the infection progresses. The condition typically begins as acute tonsillitis or pharyngitis, which then progresses to peritonsillar cellulitis (phlegmon) before ultimately forming an organized abscess. The most common causative organisms include Group A Streptococcus (Streptococcus pyogenes), though the infection is often polymicrobial, involving both aerobic and anaerobic bacteria from the oral flora.

The anatomy of the peritonsillar space plays a crucial role in understanding this condition. The space is bounded medially by the fibrous capsule of the palatine tonsil and laterally by the superior constrictor muscle. Superiorly, it extends to the soft palate, while inferiorly it communicates with the parapharyngeal space. This anatomical relationship explains why untreated peritonsillar abscesses can potentially spread to deeper neck spaces, leading to serious complications. The abscess typically forms at the superior pole of the tonsil, causing characteristic physical findings including uvular deviation, palatal bulging, and trismus due to irritation of the internal pterygoid muscle.

The clinical significance of peritonsillar abscess extends beyond its local effects. As the most common deep neck space infection requiring emergency treatment, it represents a condition where delayed diagnosis or inadequate treatment can result in airway compromise, sepsis, or extension into adjacent spaces causing mediastinitis or necrotizing fasciitis. The condition has been recognized since ancient times, with Hippocrates describing the use of incision and drainage for "quinsy." Modern management combines timely drainage procedures with appropriate antibiotic therapy, dramatically reducing the historical mortality rate. Understanding the pathophysiology, clinical presentation, and treatment options for peritonsillar abscess is essential for healthcare providers in emergency, primary care, and otolaryngology settings.

Symptoms

Peritonsillar abscess presents with a constellation of symptoms that typically develop over 2-8 days following an episode of acute tonsillitis. The progression from tonsillitis to abscess formation is marked by worsening symptoms despite antibiotic treatment.

Primary Symptoms

  • Sore throat - severe, progressive, usually worse on one side
  • Difficulty in swallowing - odynophagia progressing to dysphagia
  • Drooling due to inability to swallow saliva
  • Trismus (lockjaw) - difficulty opening mouth fully
  • "Hot potato" voice - muffled quality due to pharyngeal edema
  • Fever, often high-grade (>38.5°C/101.3°F)
  • Malaise and generalized weakness

Throat and Neck Symptoms

  • Throat swelling - visible bulging of soft palate
  • Throat feels tight - sensation of constriction
  • Swollen lymph nodes - tender cervical lymphadenopathy
  • Neck stiffness and pain with movement
  • Halitosis (bad breath) - foul-smelling breath
  • Increased salivation and drooling

Associated Symptoms

  • Ear pain - referred otalgia on affected side
  • Headache - often severe and throbbing
  • Facial swelling on affected side
  • Difficulty breathing (in severe cases)
  • Dehydration from poor oral intake
  • Sleep disturbance due to pain and positioning

Physical Examination Findings

  • Uvular deviation away from affected side
  • Unilateral palatal bulging and erythema
  • Asymmetric tonsillar hypertrophy
  • Palatal edema with loss of normal architecture
  • Fluctuance of peritonsillar area (late finding)
  • Cervical lymphadenopathy
  • Limited mouth opening (often <3 cm)

Red Flag Symptoms

  • Respiratory distress or stridor
  • Inability to handle oral secretions
  • Signs of sepsis (hypotension, altered mental status)
  • Rapidly progressive swelling
  • Bilateral symptoms (suggesting deeper infection)
  • Chest pain (possible mediastinitis)

Causes

Peritonsillar abscess results from the progression of infection from the tonsils into the peritonsillar space. Understanding the causative factors and pathogenic mechanisms is crucial for appropriate treatment and prevention.

Primary Infectious Causes

Bacterial Pathogens

  • Group A Streptococcus (GAS): Most common aerobic pathogen
  • Staphylococcus aureus: Including MRSA strains
  • Haemophilus influenzae: More common in children
  • Streptococcus pneumoniae: Occasional pathogen
  • Klebsiella pneumoniae: In immunocompromised patients

Anaerobic Bacteria

  • Fusobacterium species: Common anaerobic pathogen
  • Prevotella species: Part of polymicrobial infection
  • Bacteroides species: Associated with severe infections
  • Peptostreptococcus: Frequently isolated
  • Actinomyces: Rare but significant

Pathogenic Mechanisms

  • Direct spread: Extension from acute tonsillitis
  • Weber gland infection: Salivary glands in supratonsillar fossa
  • Lymphatic spread: Via tonsillar lymphatics
  • Hematogenous seeding: Rare mechanism
  • Penetrating trauma: Foreign body or injury

Predisposing Conditions

Local Factors

  • Recurrent or chronic tonsillitis
  • Previous peritonsillar infections
  • Tonsillar scarring from prior infections
  • Dental infections (especially molars)
  • Periodontal disease
  • Salivary gland obstruction

Systemic Factors

  • Immunosuppression (HIV, chemotherapy)
  • Diabetes mellitus
  • Chronic corticosteroid use
  • Malnutrition
  • Chronic kidney disease
  • Autoimmune disorders

Environmental and Lifestyle Factors

  • Smoking: Impairs local immunity and healing
  • Poor oral hygiene: Increases bacterial load
  • Alcohol abuse: Compromises immune function
  • Drug use: Particularly inhaled substances
  • Crowded living conditions: Increased pathogen exposure
  • Winter season: Higher incidence of respiratory infections

Anatomical Factors

  • Cryptic tonsils with deep crypts
  • Asymmetric tonsillar anatomy
  • Previous tonsillar surgery (incomplete)
  • Congenital anomalies of pharynx
  • Enlarged adenoids contributing to infection

Risk Factors

Multiple factors increase the risk of developing peritonsillar abscess. Identifying these risk factors helps in prevention and early intervention strategies.

Demographic Risk Factors

  • Age: Peak incidence 20-40 years
  • Gender: Slight male predominance (3:2)
  • Season: Higher incidence in winter months
  • Geographic location: Urban areas with crowding
  • Socioeconomic status: Lower SES associated with higher risk

Medical History

  • Recurrent tonsillitis: Strongest predictor
  • Previous peritonsillar abscess: 10-15% recurrence rate
  • Chronic pharyngitis: Persistent throat infections
  • Infectious mononucleosis: Recent EBV infection
  • Dental infections: Particularly posterior teeth
  • Recent upper respiratory infection: Within 2-4 weeks

Lifestyle Risk Factors

  • Tobacco use: Current smoking doubles risk
  • Poor oral hygiene: Inadequate dental care
  • Alcohol abuse: Chronic heavy drinking
  • Substance abuse: Particularly inhaled drugs
  • Poor nutrition: Vitamin deficiencies
  • Inadequate sleep: Immune suppression

Immunocompromising Conditions

  • HIV/AIDS: Increased severity and complications
  • Diabetes mellitus: Poor glycemic control
  • Cancer: Particularly hematologic malignancies
  • Organ transplantation: Immunosuppressive therapy
  • Chronic steroid use: Systemic corticosteroids
  • Primary immunodeficiencies: Rare but significant

Medication-Related Factors

  • Immunosuppressive drugs
  • Recent antibiotic use (may mask symptoms)
  • Inhaled corticosteroids
  • Chemotherapy agents
  • Biologic medications

Occupational and Environmental

  • Healthcare workers (pathogen exposure)
  • Teachers and childcare workers
  • Military personnel (close quarters)
  • Exposure to irritants or allergens
  • Poor air quality environments

Diagnosis

The diagnosis of peritonsillar abscess is primarily clinical, based on history and physical examination. Imaging and laboratory tests may support the diagnosis or help identify complications.

Clinical Evaluation

History Taking

  • Duration and progression of symptoms
  • Previous episodes of tonsillitis
  • Response to prior antibiotic treatment
  • Associated symptoms (fever, difficulty swallowing)
  • Risk factors and comorbidities
  • Current medications
  • Allergies to medications

Physical Examination

  • Inspection:
    • Uvular deviation (away from abscess)
    • Unilateral tonsillar swelling
    • Palatal bulging and edema
    • Pharyngeal erythema
    • Drooling or pooling saliva
  • Palpation:
    • Cervical lymphadenopathy
    • Neck swelling or induration
    • Fluctuance (if superficial)
    • Trismus assessment

Imaging Studies

Ultrasound

  • Intraoral ultrasound: 89-95% sensitivity
  • Distinguishes abscess from cellulitis
  • Guides needle aspiration
  • No radiation exposure
  • Operator dependent

CT Scan

  • Contrast-enhanced CT: Gold standard
  • Identifies abscess location and size
  • Detects complications (parapharyngeal spread)
  • Useful for atypical presentations
  • Higher radiation exposure

MRI

  • Reserved for complex cases
  • Better soft tissue detail
  • No radiation exposure
  • Time-consuming and expensive

Laboratory Tests

  • Complete blood count:
    • Leukocytosis with left shift
    • Elevated neutrophil count
  • C-reactive protein: Elevated in infection
  • Blood cultures: If systemic signs present
  • Throat culture: Limited utility in acute setting
  • Rapid strep test: May be positive
  • Monospot test: If EBV suspected

Needle Aspiration

  • Diagnostic and therapeutic procedure
  • Confirms presence of pus
  • Provides material for culture
  • Can be definitive treatment
  • Success rate: 85-95% for diagnosis

Differential Diagnosis

  • Peritonsillar cellulitis: No formed abscess
  • Retropharyngeal abscess: Posterior location
  • Parapharyngeal abscess: Lateral neck swelling
  • Infectious mononucleosis: Bilateral findings
  • Tonsillar neoplasm: Chronic, progressive
  • Internal carotid artery aneurysm: Pulsatile mass
  • Lymphoma: Systemic symptoms
  • Epiglottitis: Different clinical picture

Treatment Options

Treatment of peritonsillar abscess involves drainage of the abscess combined with appropriate antibiotic therapy. The choice of drainage method depends on clinical factors and provider expertise.

Drainage Procedures

Needle Aspiration

  • Technique:
    • 18-gauge needle with syringe
    • Aspiration at point of maximal bulging
    • Multiple attempts may be needed
    • Can be repeated if recollection occurs
  • Success rate: 85-95% with experienced providers
  • Advantages: Less invasive, outpatient procedure
  • Disadvantages: May require repeat procedures

Incision and Drainage

  • Technique:
    • Scalpel incision at fluctuant point
    • Blunt dissection to break loculations
    • Placement of drain (optional)
    • Usually done under local anesthesia
  • Indications:
    • Failed needle aspiration
    • Large or complex abscess
    • Recurrent abscess
  • Success rate: >95% definitive drainage

Quinsy Tonsillectomy

  • Indications:
    • Recurrent peritonsillar abscess
    • History of recurrent tonsillitis
    • Failed conservative management
    • Complications present
  • Timing: Can be done acutely or interval
  • Benefits: Definitive treatment, prevents recurrence
  • Risks: Higher bleeding risk in acute setting

Antibiotic Therapy

Empiric Treatment

  • Penicillin + Metronidazole:
    • Penicillin G 2-4 million units IV q4h
    • Metronidazole 500 mg IV q8h
    • Covers streptococci and anaerobes
  • Ampicillin-Sulbactam:
    • 3 g IV q6h
    • Broad spectrum coverage
    • Single agent therapy
  • Clindamycin:
    • 600-900 mg IV q8h
    • Good anaerobic coverage
    • Alternative for penicillin allergy

Oral Antibiotics

  • Amoxicillin-Clavulanate: 875 mg PO BID
  • Clindamycin: 300-450 mg PO QID
  • Penicillin VK + Metronidazole: Combination therapy
  • Duration: 10-14 days total course

Supportive Care

  • Pain management:
    • NSAIDs for mild-moderate pain
    • Opioids for severe pain
    • Topical anesthetics (viscous lidocaine)
  • Hydration:
    • IV fluids if unable to tolerate PO
    • Encourage oral intake post-drainage
  • Corticosteroids:
    • Dexamethasone 10 mg IV single dose
    • May reduce pain and trismus
    • Controversial benefit

Hospitalization Criteria

  • Airway compromise or concern
  • Inability to tolerate oral intake
  • Systemic toxicity or sepsis
  • Failed outpatient management
  • Immunocompromised state
  • Complications present
  • Social factors preventing outpatient care

Follow-up Care

  • 24-48 hour follow-up after drainage
  • Monitor for recollection of abscess
  • Ensure completion of antibiotics
  • ENT referral for recurrent cases
  • Consider interval tonsillectomy

Prevention

Prevention of peritonsillar abscess focuses on prompt treatment of pharyngitis and tonsillitis, reducing risk factors, and considering tonsillectomy in appropriate candidates.

Primary Prevention

  • Prompt treatment of pharyngitis:
    • Early antibiotic therapy for strep throat
    • Complete prescribed antibiotic courses
    • Follow-up for persistent symptoms
  • Good oral hygiene:
    • Regular dental care
    • Twice daily brushing and flossing
    • Treatment of dental infections
    • Regular dental cleanings
  • Lifestyle modifications:
    • Smoking cessation
    • Limit alcohol consumption
    • Adequate hydration
    • Proper nutrition

Secondary Prevention

  • Tonsillectomy indications:
    • Recurrent peritonsillar abscess
    • Recurrent tonsillitis (>7 episodes/year)
    • Chronic tonsillitis unresponsive to treatment
    • Obstructive sleep symptoms
  • Management of risk factors:
    • Optimize diabetes control
    • Treat immunodeficiency when possible
    • Address chronic sinusitis
    • Manage GERD

Patient Education

  • Recognition of early symptoms
  • Importance of completing antibiotics
  • When to seek medical attention
  • Understanding recurrence risk
  • Post-treatment care instructions
  • Importance of follow-up

Environmental Measures

  • Avoid exposure to irritants
  • Maintain adequate humidity
  • Avoid sharing utensils during illness
  • Hand hygiene practices
  • Avoid crowded spaces during outbreaks

Special Populations

  • Immunocompromised patients:
    • Prophylactic antibiotics in some cases
    • Lower threshold for treatment
    • Regular monitoring
  • Children:
    • Appropriate antibiotic dosing
    • Consider adenoidectomy if indicated
    • Monitor growth and development

When to See a Doctor

Seek immediate emergency care for:

  • Difficulty breathing or noisy breathing (stridor)
  • Inability to swallow saliva (drooling excessively)
  • Severe throat swelling with voice changes
  • High fever with confusion or altered mental status
  • Chest pain or neck swelling extending downward
  • Signs of airway obstruction
  • Severe dehydration from inability to drink

Urgent medical evaluation needed for:

Schedule appointment for:

  • Recurrent episodes of tonsillitis
  • Persistent throat feels tight sensation
  • Chronic bad breath with throat discomfort
  • History of peritonsillar abscess
  • Evaluation for tonsillectomy
  • Post-treatment follow-up

Related Conditions

Frequently Asked Questions

How quickly does a peritonsillar abscess develop?

A peritonsillar abscess typically develops over 2-8 days following acute tonsillitis or pharyngitis. The progression from sore throat to abscess formation is usually marked by worsening symptoms despite antibiotic treatment, with the development of unilateral throat pain, difficulty swallowing, and trismus.

Can peritonsillar abscess be treated without drainage?

While very early peritonsillar cellulitis (before abscess formation) may respond to antibiotics alone, once an abscess has formed, drainage is necessary. Antibiotics alone have a high failure rate for established abscesses. Drainage combined with antibiotics provides the most effective treatment.

What is the recurrence rate of peritonsillar abscess?

The recurrence rate is approximately 10-15% after the first episode. Risk factors for recurrence include young age, previous episodes of tonsillitis, and smoking. Many ENT specialists recommend tonsillectomy after a second peritonsillar abscess to prevent future episodes.

Is peritonsillar abscess contagious?

The abscess itself is not contagious, but the underlying bacterial infection (particularly Group A Streptococcus) that led to the abscess can be transmitted to others through respiratory droplets. Good hygiene and avoiding close contact during acute illness is recommended.

How long is the recovery after drainage?

Most patients experience significant improvement within 24-48 hours after drainage. Complete recovery typically takes 7-10 days with appropriate antibiotic therapy. Patients can usually return to normal activities within a few days, though full healing of the tissues may take 2-3 weeks.

References

  1. Galioto NJ. Peritonsillar Abscess. Am Fam Physician. 2017;95(8):501-506.
  2. Klug TE, Greve T, Hentze M. Complications of peritonsillar abscess. Ann Clin Microbiol Antimicrob. 2020;19(1):32.
  3. Battaglia A, Burchette R, Hussman J, Silver MA, Martin P, Bernstein P. Comparison of Medical Therapy Alone to Medical Therapy with Surgical Treatment of Peritonsillar Abscess. Otolaryngol Head Neck Surg. 2018;158(2):280-286.
  4. Chang BA, Thamboo A, Burton MJ, Diamond C, Nunez DA. Needle aspiration versus incision and drainage for the treatment of peritonsillar abscess. Cochrane Database Syst Rev. 2016;12(12):CD006287.
  5. Hidaka H, Kuriyama S, Yano H, Tsuji I, Kobayashi T. Precipitating factors in the pathogenesis of peritonsillar abscess and bacteriological significance of the Streptococcus milleri group. Eur J Clin Microbiol Infect Dis. 2021;40(3):543-549.