Diagnosis and Management of Streptococcal Pharyngitis

Clinical Scoring Systems

The American College of Physicians recommends using the Centor criteria or modified McIsaac score to determine which patients need laboratory testing, but never treat based on clinical score alone—always confirm with rapid antigen detection test (RADT) or throat culture before prescribing antibiotics 1, 2, 3
The Centor criteria assigns points based on clinical features, including fever, absence of cough, tender anterior cervical lymphadenopathy, and tonsillar swelling or exudate, with each feature assigned 1 point 1, 2

Patients with a score of 0-1 have a very low probability of Group A Streptococcus (GAS) and should not undergo testing, but instead be treated symptomatically with analgesics only 1, 4
Patients with a score of 2-3 should perform RADT or throat culture, with backup culture recommended for children and adolescents due to low RADT sensitivity in pediatrics 1, 2
Patients with a score of 4 have a high probability of GAS infection, but laboratory confirmation is still recommended before treatment, as even patients with all clinical features have confirmed streptococcal pharyngitis only 35-50% of the time 1, 2

The Infectious Diseases Society of America recommends that children under 3 years should not be tested routinely for GAS pharyngitis, as it is uncommon in this age group and acute rheumatic fever is exceptionally rare 5, 6
The peak age for testing is 5-15 years, when GAS causes 15-30% of acute pharyngitis cases, according to the American Academy of Pediatrics 2, 6
Adults have a lower disease prevalence (5-15% of pharyngitis), making the threshold for testing appropriately higher, as stated by the American College of Physicians 1, 2

The American Heart Association recommends penicillin V as first-line therapy for GAS pharyngitis, with a dosage of 250 mg twice or three times daily for 10 days 4, 7
For patients with penicillin allergy, the Infectious Diseases Society of America recommends alternative antibiotics, such as first-generation cephalosporins, clindamycin, clarithromycin, or azithromycin 4, 7

The American College of Physicians states that antibiotics provide modest symptom relief, shortening duration by 1-2 days, and prevent acute rheumatic fever, suppurative complications, and disease transmission to close contacts 1, 5
Treatment within 9 days of symptom onset still prevents acute rheumatic fever, according to the American Heart Association 3