Diagnosis and Management of Streptococcal Pharyngitis

Clinical Assessment

• The Centor score consists of four equally-weighted clinical features, each worth one point: fever by history, tonsillar exudates, tender anterior cervical lymphadenopathy, and absence of cough, with the score directly correlating with the probability of Group A streptococcal (GAS) infection 1, 2
• Each criterion in the Centor score receives one point for a maximum score of 4, which helps in assessing the probability of GAS infection 2

Risk Stratification

• Patients with a score of 0 have a 2.5-8% probability of GAS pharyngitis, while those with a score of 1 have a 5-12% probability, a score of 2 has an 11-23% probability, a score of 3 has a 28-38% probability, and a score of 4 has a 51-57% probability 1

Management Algorithm

• For patients with scores 0-2, symptomatic management only is recommended, without testing or antibiotic treatment, using ibuprofen or acetaminophen for pain relief 1, 2, 3
• For patients with scores 3-4, a rapid antigen detection test (RADT) should be performed, and antibiotic treatment should only be given if the test is positive 1, 2, 3

Antibiotic Treatment

• The American Academy of Pediatrics and the Infectious Diseases Society of America recommend penicillin or amoxicillin for 10 days as first-line therapy for GAS pharyngitis 4, 3
• For penicillin-allergic patients, treatment options include first-generation cephalosporin, clindamycin, clarithromycin, or azithromycin for 10 days or 5 days, respectively 4

Testing Considerations

• In adults, negative RADTs do not require backup throat culture, while in children and adolescents, negative RADTs should be backed up by throat culture 3
• Positive RADTs do not require backup culture due to high specificity (≥95%) 3, 1

Important Clinical Caveats

• The Centor score has low positive predictive value, even with high scores, and was validated only in adults, not children 1, 2
• Antibiotic benefits are modest, reducing symptoms by 1-2 days, and must be weighed against side effects, antibiotic resistance, and costs 1, 2
• Antibiotics should not be given to children under 3 years old, patients with clear viral features, or asymptomatic household contacts 4, 3