Peritonsillar Cellulitis: Diagnosis and Treatment
Immediate Clinical Diagnosis
Peritonsillar cellulitis can be diagnosed clinically based on the characteristic presentation of unilateral tonsillar bulge, uvular deviation, trismus, muffled "hot potato" voice, and fever, without requiring imaging or aspiration when no fluctuant collection is present. 1
The key distinguishing features that confirm peritonsillar cellulitis (rather than abscess) include:
- Soft palate bulging without fluctuance on palpation 2
- Younger age (mean 10.8 years for cellulitis vs 15.0 years for abscess, though adolescents and young adults are commonly affected) 2
- Trismus as a discriminating feature for cellulitis specifically 2
- Unilateral tonsillar enlargement with erythema 2, 3
- Uvular deviation (present in approximately one-third of cases) 2
- Anterior cervical lymphadenopathy 1
Critical Diagnostic Pitfall
Do not perform needle aspiration if the presentation is consistent with cellulitis alone (no fluctuance, earlier stage). However, if there is any uncertainty about whether pus is present, needle puncture of the swollen soft palate is required to distinguish cellulitis from abscess. 3, 4
When Imaging Is Required
CT scan with IV contrast is NOT needed for typical peritonsillar cellulitis but should be obtained if: 1
- Atypical presentation
- Concern for deep neck space extension (retropharyngeal or parapharyngeal involvement)
- Inability to adequately examine the oropharynx
- Clinical deterioration despite appropriate therapy
Antibiotic Treatment Protocol
Initiate antibiotics immediately targeting Group A Streptococcus and oral anaerobes, with first-line therapy being amoxicillin-clavulanate or ampicillin-sulbactam. 1, 5
Specific Antibiotic Regimens:
First-line options:
Alternative for penicillin allergy:
Other acceptable alternatives:
- Cephalosporins (first-generation) 4
- Metronidazole (must be combined with coverage for streptococci) 4
Duration of Therapy
Treat for 10 days to ensure eradication of Group A Streptococcus, consistent with standard treatment for streptococcal pharyngitis and its complications. 6, 7
Disposition Decision Algorithm
Outpatient management is appropriate if ALL of the following criteria are met: 1
- No airway compromise
- Able to tolerate oral intake and medications
- Clinical improvement after initial treatment
- Reliable follow-up within 24-48 hours available
- No immunocompromise
Hospitalization is mandatory if ANY of the following are present: 1
- Airway compromise or signs of respiratory distress
- Inability to tolerate oral intake or medications
- Failed outpatient management
- Concern for deep neck space extension
- Immunocompromised status
Supportive Care
Provide aggressive supportive therapy including: 5, 4
- Analgesics (acetaminophen or NSAIDs) for pain control
- Hydration maintenance (IV fluids if unable to tolerate oral intake)
- Consider corticosteroids to reduce symptoms and speed recovery 5
Expected Clinical Course
Patients with peritonsillar cellulitis treated with IV penicillin should show clinical improvement within 24-48 hours. 2 If no improvement occurs, this suggests either:
- Progression to abscess formation requiring drainage 2, 8
- Inadequate antibiotic coverage
- Deep neck space involvement requiring imaging 1
Critical Management Pitfall
The most important error to avoid is delaying treatment while waiting for imaging or laboratory confirmation. Peritonsillar cellulitis is a clinical diagnosis in typical presentations, and antibiotics should be started immediately based on clinical findings alone. 1, 5 The microbiology is predictable (Group A and non-Group A beta-hemolytic streptococci, Streptococcus pneumoniae, and oral anaerobes), making empiric therapy highly effective. 2, 5