What is the next step for a female patient with persistent sore throat after completing a 10-day course of amoxicillin (amoxicillin) without symptom resolution, with a history of poorly fitting dentures?

Do Not Extend Antibiotic Therapy—Investigate Alternative Causes

The next step is to discontinue antibiotics and perform a thorough oral examination focusing on the poorly fitting dentures as the likely cause of persistent symptoms, rather than extending antibiotic therapy. 1 The patient has completed an appropriate 10-day course of amoxicillin without symptom resolution, and the presence of poorly fitting dentures strongly suggests a mechanical rather than infectious etiology.

Why Extending Antibiotics is Inappropriate

• Simply repeating or extending the same antibiotic has a high failure rate and delays appropriate treatment. 1 The patient has already completed a full 10-day course of amoxicillin, which is the recommended duration for streptococcal pharyngitis. 2, 3

• Treatment should be continued for a minimum of 48 to 72 hours beyond the time that the patient becomes asymptomatic or evidence of bacterial eradication has been obtained. 3 Since the patient remains symptomatic after 10 days, this suggests either treatment failure requiring a different approach or an alternative diagnosis.

• Antibiotics provide modest symptom reduction in bacterial pharyngitis, with 82% of patients symptom-free by one week even without treatment. 4 Persistent symptoms beyond 10 days of appropriate antibiotic therapy strongly suggest a non-infectious cause.

Critical Next Steps

1. Immediate Re-evaluation Required

• Re-evaluate the patient to determine if the persistent sore throat represents treatment failure, reinfection, or an alternative diagnosis. 1 Given the history of poorly fitting dentures, mechanical trauma is the most likely explanation.

• Obtain a throat culture or rapid antigen detection test (RADT) immediately to determine if Group A Streptococcus (GAS) is still present. 1 A negative RADT should be confirmed with throat culture to rule out false negatives. 1

• If the culture is negative for GAS, the persistent sore throat is likely viral or due to another non-streptococcal cause, and antibiotics should not be continued. 1

2. Address the Denture Issue

• Poorly fitting dentures commonly cause persistent oral pain and can lead to ulcers, stomatitis, hyperplasia, and chronic candidiasis. 5 This mechanical trauma can easily mimic or perpetuate infectious pharyngitis symptoms.

• Perform a thorough oral examination looking specifically for:

  • Denture-induced ulcerations or erosions on the palate, gingiva, or buccal mucosa 5
  • Signs of chronic candidiasis (white plaques, erythema) 5
  • Mucosal hyperplasia or irritation at denture contact points 5
  • Evidence of bone resorption if dentures have been ill-fitting for extended periods 5

3. If GAS Persists (Treatment Failure)

Only if the throat culture remains positive for GAS after completing 10 days of amoxicillin should you consider treatment failure requiring a different antibiotic approach. 1

• Clindamycin 300 mg three times daily for 10 days is the preferred treatment for penicillin failure in adults, with approximately 1% resistance rates in the United States. 1, 6 Clindamycin can protect patients from recurrence for at least 3 months following treatment failure with penicillin. 6

• Amoxicillin-clavulanate 875 mg twice daily for 10 days is an effective alternative that addresses beta-lactamase-producing co-pathogens. 1 This is particularly relevant as co-pathogenicity (where bacteria susceptible to penicillin are protected by other colocalized bacterial strains) is a recognized cause of penicillin treatment failure. 7

• Do not use macrolides (azithromycin, clarithromycin) as first-line alternatives for treatment failure unless the patient has documented immediate/anaphylactic penicillin allergy, due to resistance rates ranging from 5-8% in the United States. 1

Common Pitfalls to Avoid

• Do not assume non-compliance without confirmation. 1 While lack of compliance is a primary cause of penicillin treatment failure, 7 the patient reports completing the full 10-day course.

• Do not ignore the denture issue. 5 Mechanical trauma from poorly fitting dentures can cause persistent symptoms that will not respond to antibiotics and may lead to malignant changes if left unaddressed. 5

• Do not prescribe broader-spectrum antibiotics empirically without confirming persistent bacterial infection. 1 This contributes to antimicrobial resistance without addressing the likely mechanical cause.

Symptomatic Management

• Provide symptomatic relief with ibuprofen or acetaminophen for throat pain while investigating the underlying cause. 1

• Refer to dentistry for denture adjustment or replacement if oral examination confirms denture-related trauma as the cause of symptoms.

• Consider evaluation for chronic candidiasis if oral examination reveals findings consistent with fungal infection, which commonly occurs under poorly fitting dentures. 5