What is the recommended treatment for an adult patient with tonsillitis?

Treatment of Tonsillitis in Adults

Adults with tonsillitis should receive antibiotics ONLY if Group A Streptococcus (GAS) is confirmed by rapid antigen detection test (RADT) or throat culture, with penicillin V 500 mg twice daily or amoxicillin 1000 mg once daily for 10 days as first-line treatment. 1, 2

Diagnostic Approach Before Treatment

Do not prescribe antibiotics without microbiological confirmation. 1, 2

• Use the Centor/McIsaac criteria to determine who needs testing: fever by history, tonsillar exudates, tender anterior cervical adenopathy, and absence of cough 1
• Patients with 0-2 Centor criteria should NOT be tested or treated, as viral etiology is most likely 2, 3
• Patients with 3-4 Centor criteria warrant RADT and/or throat culture before prescribing antibiotics 1, 2
• Viral features that argue AGAINST testing include: cough, rhinorrhea, hoarseness, oral ulcers, conjunctivitis, or diarrhea 1

First-Line Antibiotic Treatment for Confirmed GAS

Penicillin V is the drug of choice due to narrow spectrum, proven efficacy, low cost, and lack of resistance 1, 2, 4:

• Dosage: 500 mg twice daily OR 250 mg four times daily for 10 days 1, 2
• The 10-day duration is critical and non-negotiable to maximize bacterial eradication and prevent rheumatic fever 1, 2, 4

Amoxicillin is an equally acceptable first-line alternative 1, 2, 4:

• Dosage: 1000 mg once daily OR 500 mg twice daily for 10 days 1, 2
• May provide faster symptom relief (sore throat resolution by day 2) compared to penicillin 5

Treatment for Penicillin-Allergic Patients

For non-anaphylactic penicillin allergy, use first-generation cephalosporins 1, 2:

• Cephalexin 500 mg twice daily for 10 days 1, 2
• Cefadroxil 1 g once daily for 10 days 1, 2

For anaphylactic penicillin allergy or Type I hypersensitivity, use 1, 2, 3:

• Clindamycin 300 mg three times daily for 10 days (preferred) 1, 2
• Azithromycin 500 mg once daily for 5 days 1
• Clarithromycin 250 mg twice daily for 10 days 1

Important caveat: Macrolides (azithromycin, clarithromycin) have known geographic and temporal resistance patterns to GAS, making them less reliable 1, 6

Symptomatic Treatment (For All Patients)

Provide analgesic therapy regardless of antibiotic use 1:

• Acetaminophen or NSAIDs (ibuprofen, aspirin in adults) for pain and fever 1, 2
• Throat lozenges for topical relief 1
• Salt water gargles (though limited evidence) 1, 3
• Do NOT use aspirin in children due to Reye syndrome risk 1
• Do NOT use corticosteroids for routine GAS pharyngitis 1

Management of Treatment Failure or Recurrent Tonsillitis

If symptoms return within 2 weeks of completing therapy, consider 2, 3:

• Clindamycin 300 mg three times daily for 10 days (preferred for recurrent GAS) 1, 2, 3
• Amoxicillin-clavulanate 875/125 mg twice daily for 10 days 2, 3
• Penicillin G benzathine 1.2 million units IM (single dose) plus rifampin 1, 3

Consider chronic GAS carrier state if patient has repeated positive tests with viral symptoms (cough, rhinorrhea) between episodes 1, 3. Chronic carriers do NOT require antibiotics unless specific high-risk situations exist 1, 3.

When to Consider Tonsillectomy

Watchful waiting is strongly recommended unless Paradise criteria are met 2, 4, 7:

• ≥7 documented episodes in the past year, OR
• ≥5 episodes per year for 2 consecutive years, OR
• ≥3 episodes per year for 3 consecutive years 2, 4, 7

Each episode must be documented with temperature ≥38.3°C, cervical adenopathy, tonsillar exudate, OR positive GAS test 2, 3, 4

Tonsillectomy is NOT recommended solely to reduce frequency of GAS pharyngitis in adults 1, 4

Critical Pitfalls to Avoid

• Never prescribe antibiotics without confirming GAS infection through RADT or culture 1, 2, 4
• Never use courses shorter than 10 days for penicillin or amoxicillin, as this increases treatment failure risk 2, 4, 6
• Never use broad-spectrum antibiotics when narrow-spectrum penicillins are effective for confirmed GAS 2, 4
• Never perform follow-up throat cultures on asymptomatic patients who completed appropriate therapy 1, 2, 3
• Never treat based on ASO titers, as they reflect past immunologic response, not current infection 3

Expected Clinical Outcomes

Antibiotics provide modest benefit in confirmed GAS tonsillitis 1:

• Shorten duration of sore throat by 1-2 days 1
• Number needed to treat: 6 patients at 3 days, 21 patients at 1 week 1
• Primary benefit is preventing complications (rheumatic fever, peritonsillar abscess) rather than symptom relief 1
• Most viral tonsillitis resolves within 1 week without antibiotics 1