What is the recommended treatment for an adult or adolescent patient with a history of recent exposure to someone with a similar illness or a weakened immune system, presenting with headache, fever, and sore throat, diagnosed with group G streptococcal (G strep) infection?

Treatment of Group G Streptococcal Pharyngitis

For Group G streptococcal pharyngitis with headache, fever, and sore throat, treat with penicillin V 250 mg four times daily (or 500 mg twice daily) for 10 days in adults, or amoxicillin 500 mg twice daily for 10 days as an alternative first-line option. 1

Confirming the Diagnosis

Before initiating treatment, confirm Group G streptococcus through throat culture, as rapid antigen detection tests are designed specifically for Group A streptococcus and will not detect Group G streptococcus 1. The clinical presentation of Group G streptococcal pharyngitis mirrors that of Group A streptococcus—sudden onset of sore throat, fever, headache, and tender anterior cervical lymphadenopathy without prominent cough or rhinorrhea 1, 2.

First-Line Antibiotic Treatment

For Penicillin-Tolerant Patients

• Penicillin V remains the preferred treatment due to its narrow spectrum, proven efficacy, safety, and low cost 1, 3
• Dosing for adults: 250 mg orally four times daily OR 500 mg twice daily for 10 days 1, 3
• Dosing for adolescents: 250 mg orally three to four times daily OR 500 mg twice daily for 10 days 1
• Amoxicillin is an equally effective alternative at 500 mg twice daily for 10 days in adults, often preferred due to better palatability and simplified dosing 1, 4
• Benzathine penicillin G intramuscular injection provides single-dose treatment: 1.2 million units for patients ≥27 kg 1, 3

Critical Treatment Duration

• The full 10-day course is essential to achieve maximal bacterial eradication and prevent complications, even if symptoms resolve in 3-4 days 1, 3, 5
• Incomplete treatment courses lead to treatment failure and potential complications 1
• Therapy can be safely initiated up to 9 days after symptom onset and still prevent complications 6

Treatment for Penicillin-Allergic Patients

Non-Anaphylactic Penicillin Allergy

• First-generation cephalosporins are the preferred alternative with strong, high-quality evidence 1, 6
• Cephalexin 500 mg orally twice daily for 10 days (adults) 6
• Cross-reactivity risk is only 0.1% in patients with non-severe, delayed penicillin reactions 6

Immediate/Anaphylactic Penicillin Allergy

• Clindamycin is the preferred choice for patients with anaphylaxis, angioedema, or immediate urticaria to penicillin 1, 6
• Dosing: 300 mg orally three times daily for 10 days (adults) 1, 6
• Clindamycin has approximately 1% resistance rate among streptococci in the United States 6
• Avoid all cephalosporins in patients with immediate hypersensitivity due to up to 10% cross-reactivity risk 6, 1

Alternative Macrolides (Less Preferred)

• Azithromycin 500 mg once daily for 5 days OR clarithromycin 250 mg twice daily for 10 days 6, 1
• Macrolide resistance is 5-8% in the United States and varies geographically 6
• These should be reserved for patients who cannot tolerate both penicillin and clindamycin 6

Symptomatic Management

• Acetaminophen or NSAIDs (such as ibuprofen) should be offered for moderate to severe symptoms or fever control 1, 7
• NSAIDs are more effective than acetaminophen for pain and fever associated with streptococcal pharyngitis 2
• Aspirin must be avoided in children due to risk of Reye syndrome 1, 7
• Corticosteroids are not recommended for routine use, as they provide only minimal symptom reduction with potential adverse effects 1, 7
• Warm salt water gargles and topical anesthetic lozenges may provide temporary relief 7

Management of Recurrent Episodes

• For the first recurrence, retreat with any appropriate first-line agent 1
• For multiple recurrences, consider whether the patient is a chronic carrier experiencing viral infections rather than true recurrent bacterial infections 1
• Clindamycin demonstrates superior eradication rates in chronic carriers and treatment failures 6, 1
• Chronic carriers generally do not require treatment unless special circumstances exist (community outbreak, family history of rheumatic fever, or excessive anxiety) 6

Critical Pitfalls to Avoid

• Do not rely on rapid antigen detection tests for Group G streptococcus—they only detect Group A streptococcus 1
• Do not shorten the antibiotic course below 10 days (except azithromycin's 5-day regimen), as this dramatically increases treatment failure and complication risk 1, 6
• Do not use cephalosporins in patients with anaphylactic penicillin reactions due to 10% cross-reactivity 6, 1
• Do not prescribe antibiotics without diagnostic confirmation through throat culture 1
• Routine post-treatment cultures are not recommended for asymptomatic patients who completed therapy 1

Special Considerations for Immunocompromised or High-Risk Patients

• Patients with weakened immune systems or recent exposure to similar illness should receive the same standard treatment regimens 1
• Consider clindamycin for severe invasive infections, though Group G streptococcus rarely causes invasive disease compared to Group A 6
• If fever persists beyond 48-72 hours of appropriate antibiotic therapy, consider treatment failure or development of suppurative complications (peritonsillar abscess, cervical lymphadenitis) requiring imaging and possible surgical intervention 7