What is the treatment for a single swollen tonsil?

Treatment for a Single Swollen Tonsil

A single swollen tonsil requires immediate evaluation to exclude malignancy, peritonsillar abscess, and sexually transmitted infections (particularly syphilis), followed by testing for Group A Streptococcus before initiating any treatment. 1, 2

Critical Red Flags Requiring Urgent Evaluation

Unilateral tonsillar enlargement is NOT typical of routine infectious tonsillitis and demands a different diagnostic approach than bilateral disease. 2, 3

• Malignancy must be excluded first - any persistent unilateral tonsillar enlargement, especially with induration, ulceration, or fixation to surrounding tissues, requires urgent ENT referral and possible biopsy 3
• Peritonsillar abscess - look for severe unilateral throat pain, trismus, "hot potato voice," uvular deviation away from the affected side, and inability to swallow secretions 4
• Primary syphilis - in sexually active adults, particularly with history of oral intercourse, obtain rapid plasma reagin (RPR) and Treponema pallidum antibody testing; Gram stain of tonsillar exudate may show gram-negative corkscrew spirochetes 2
• Anaerobic necrotizing infections - Prevotella species can cause unilateral necrotizing tonsillitis with severe tissue destruction; requires anaerobic culture with proper transport media 3

Diagnostic Algorithm

Step 1: Perform rapid antigen detection test (RADT) and/or throat culture for Group A Streptococcus, but recognize that a negative test does NOT rule out serious pathology in unilateral presentation. 1, 2

Step 2: Obtain sexual history and consider syphilis testing (RPR and T. pallidum antibody) in all sexually active adults with unilateral tonsillar swelling. 2

Step 3: If the patient has severe symptoms (trismus, drooling, muffled voice, respiratory distress), obtain CT scan with contrast to evaluate for abscess. 4

Step 4: If symptoms persist beyond 2 weeks despite appropriate antibiotic therapy, or if there is progressive enlargement, refer urgently to ENT for possible biopsy to exclude malignancy. 3

Treatment Based on Diagnosis

If Group A Streptococcus Confirmed:

• Penicillin V 500 mg orally twice daily for 10 days (or amoxicillin 500 mg twice daily for 10 days) is first-line treatment 1, 5
• For penicillin allergy without anaphylaxis: first-generation cephalosporin 1
• For anaphylactic penicillin allergy: clindamycin 300 mg three times daily, azithromycin, or clarithromycin 1
• The full 10-day course is mandatory to prevent rheumatic fever and glomerulonephritis, even if symptoms resolve earlier 1

If Syphilis Confirmed:

• Benzathine penicillin G 2.4 million units intramuscularly as a single dose is the treatment for primary syphilis 2

If Peritonsillar Abscess:

• Requires needle aspiration or incision and drainage under local or general anesthesia 4
• Empiric antibiotics covering streptococci and anaerobes (amoxicillin-clavulanate or clindamycin) 4

If Anaerobic Infection (Prevotella):

• Requires antibiotics with anaerobic coverage: amoxicillin-clavulanate, clindamycin, or metronidazole plus penicillin 3

Supportive Care for All Cases

• Acetaminophen or NSAIDs for pain control 1
• Adequate hydration 5
• Saltwater gargles 5

When Tonsillectomy Is NOT Indicated

Tonsillectomy should NOT be performed for a single episode of unilateral tonsillitis. 6, 1

• Tonsillectomy is only considered for recurrent infections meeting Paradise criteria: ≥7 episodes in past year, ≥5 episodes/year for 2 years, or ≥3 episodes/year for 3 years 6, 1
• Each episode must be documented with temperature >38.3°C, cervical adenopathy, tonsillar exudate, or positive GAS test 6, 1
• Watchful waiting for 12 months is recommended even when Paradise criteria are met, as spontaneous improvement occurs in most cases 6

Critical Pitfalls to Avoid

• Never assume unilateral tonsillar enlargement is simple bacterial tonsillitis - the differential diagnosis is much broader and includes life-threatening conditions 2, 3
• Never start antibiotics without testing for GAS in typical presentations, but recognize that negative testing doesn't exclude other serious causes in unilateral disease 1, 2
• Never delay ENT referral if symptoms persist beyond 2 weeks or if there are concerning features for malignancy 3
• Never prescribe antibiotic courses shorter than 10 days for confirmed GAS tonsillitis 1
• Never perform routine follow-up throat cultures in asymptomatic patients who completed appropriate therapy 1