From the Guidelines
Strep throat should be tested and treated when symptoms like severe sore throat, fever, swollen tonsils with white patches, and swollen lymph nodes are present, especially without cough or cold symptoms, as indicated by the modified Centor criteria 1. Testing typically involves a rapid strep test or throat culture. The standard treatment is penicillin (typically penicillin V 250-500 mg orally twice daily for 10 days) or amoxicillin (500 mg twice daily or 1000 mg once daily for 10 days) as recommended by the American Heart Association 1. For penicillin-allergic patients, alternatives include cephalexin (if no anaphylactic reaction history), azithromycin, or clindamycin. Some key points to consider when testing and treating strep throat include:
- The use of the modified Centor criteria to determine the likelihood of a bacterial cause of pharyngitis 1
- The importance of completing the full antibiotic course, even if symptoms improve quickly, to prevent complications like rheumatic fever 1
- The need for patients to stay home from work or school for 24 hours after starting antibiotics to prevent spreading the infection 1
- The role of streptococcal antibody tests in confirming a recent GAS infection and identifying nonsuppurative complications like acute rheumatic fever or acute glomerulonephritis 1
- The potential for misinterpretation of streptococcal antibody titers due to variations in normal levels among different age groups and the need for standardization of newer tests 1
From the Research
Importance of Testing and Treating Strep Throat
- Strep throat is a common infection responsible for more than 6 million office visits in the United States annually 2
- Only 10% of adults seeking care for a sore throat have group A beta-hemolytic streptococcal pharyngitis, but 60% or more are prescribed antibiotics 2
- Guidelines recommend using clinical decision rules to assess the risk of group A beta-hemolytic streptococcal infection, followed by rapid antigen testing if a diagnosis is unclear, before prescribing antibiotics 2, 3
When to Test for Strep Throat
- Fever, tonsillar exudate, cervical lymphadenitis, and patient ages of 3 to 15 years increase clinical suspicion of strep throat 2
- A cough is more suggestive of a viral etiology 2, 3
- The modified Centor score can be used to help physicians decide which patients need no testing, throat culture/rapid antigen detection testing, or empiric antibiotic therapy 3
Diagnostic Methods
- Throat culture is considered the diagnostic standard, although the sensitivity and specificity of rapid antigen detection testing have improved significantly 3, 4
- Rapid antigen tests (RAT) have been developed for faster diagnosis, with the BD Veritor ™ System showing high sensitivity and specificity 4
- Nucleic acid amplification tests and machine learning and artificial intelligence are also available diagnostic methods 5
Treatment of Strep Throat
- Penicillin and amoxicillin are first-line antibiotics, with a recommended course of 10 days 2, 3
- First-generation cephalosporins are recommended for patients with nonanaphylactic allergies to penicillin 2, 3
- Antibiotics with narrow spectrums of activity are appropriate for treating strep throat, but the decision to prescribe antibiotics remains a controversial question 5