Most cases of infectious pharyngitis are caused by viral causes with between 5-15% being caused by Group A beta-hemolytic streptococcus (GABHS).
The rationale behind treating GABHS pharyngitis is the prevention of rheumatic fever, glomerulonephritis, other suppurative complications, and to more rapidly improve symptoms.
Current data supports:
- In the U.S. would need to treat 3-4,000 patients with GABHS to prevent a single case of rheumatic fever
- Antibiotic therapy has never been shown to prevent glomerulonephritis
- Treatment of pharyngitis does not appear to reduce risk for peritonsillar abscess
- Antibiotics started within 2-3 days of symptom onset in cases of GABHS pharyngitis hastens symptomatic improvement by 1-2 days
Recommendations for diagnosis:
- Use of Centor criteria
- Tonsillar exudates
- Tender anterior cervical Lymphadenopathy
- Absence of cough
- History of fever
- Use of rapid streptococcal antigen testing
- Presence of 1 Centor criteria = No further testing and no antibiotic treatment
- Presence of 2-4 Centor criteria = Perform rapid streptococcal antigen test and if positive administer antibiotic therapy
- In children & adolescents, a negative rapid streptococcal antigen test should be confirmed with a culture (unless the practitioner has determined their rapid streptococcal antigen testing to be comparable to throat culture in their practice)
- Rationale for not confirming a negative rapid streptococcal antigen test with a culture in adults is that risk of rheumatic fever is much lower in adults than children and a negative rapid streptococcal antigen test reasonably rules out the diagnosis
Recommendations for treatment:
- Use penicillins whenever possible unless allergy is present
- Where penicillin allergy is present
- Erythromycin (other macrolides may be substituted)
- If GABHS resistance to macrolides present in community
- Use cephalosporins (if patient has mild penicillin allergy)
- Use Clindamycin (if patient has severe penicillin allergy)
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