Guideline for diagnosis, treatment of strep throat

Only confirmed cases of group A streptococcal pharyngitis, or strep throat, should be treated with antibiotics, according to an updated 2012 guideline issued by the Infectious Diseases Society of America (IDSA).

An estimated 15 million persons in the United States visit their physicians for sore throats every year, but only 5% to 15% of adults and 20% to 30% of children actually have group A streptococcal pharyngitis. The other cases are viral infections that do not respond to antibiotics.

A rapid antigen detection test will help confirm that only cases of group A strep will be treated with antibiotic therapy, says the IDSA. Using antibiotics inappropriately leads to developing resistance to the drugs.

Positive rapid test results do not need a confirming throat culture because the tests are highly specific for group A strep and false positives are rare. Physicians can begin treating patients with narrow-spectrum penicillin or amoxicillin for a 10-day duration without further testing. Broad-spectrum drugs such as azithromycin or cephalosporin are not recommended except in cases of allergy to penicillin.

Negative tests in children and adolescents, however, should be confirmed with throat cultures. Adults have a low rate of group A strep infection and a low risk for complications such as acute rheumatic fever, so confirming with a throat culture is not warranted.

Testing for group A strep in children aged younger than 3 years is not indicated because of the low rate of infection in this age group, but testing may be considered if a child’s older sibling has a confirmed strep infection.

The guideline also suggests using acetaminophen or nonsteroidal inflammatory drugs in addition to antibiotics to treat fever but advises against using aspirin in children or adding corticosteroid therapy.

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