Children and adolescents with a sore throat and a negative rapid diagnostic test for group A strep, also referred to as GAS, should have a culture performed to confirm that they don't have strep throat, say new guidelines from the Infectious Diseases Society of America (IDSA).
Conversely, the IDSA advises against confirmatory throat cultures for adults with negative rapid strep tests because adults have lower rates of strep throat and far lower risk of complications, such as rheumatic fever, than do children. Regardless of patient age, the guidelines affirm that a positive rapid antigen detection test does not need further confirmation with a throat culture because the rapid tests are highly specific and false-positives are rare. These guidelines update 2002 recommendations from the IDSA and were published online Sept. 10 and in the October issue of the journal Clinical Infectious Disease.
Occurring most often in winter and early spring, strep throat is a common illness, especially among children ages 5 to 15 years, and is typically treated with a course of antibiotics. However, viruses are to blame for the majority of illnesses featuring a sore, inflamed throat, and antibiotics are ineffective in treating viral infections. While group A strep is the most common bacterial cause of sore throat, it is responsible for only 5%–15% of adults' visits to doctors for sore throat and 20%–30% of children's, say the guidelines. Yet nationally, up to 70% of primary care patients with sore throats receive prescriptions for antibiotics, prompting concern about antibiotic resistance to medications used to treat group A strep.
Rapid strep tests help ensure that only positively identified cases of group A strep get treatment with antibiotics. At the same time, the guidelines emphasize the importance of early, accurate diagnosis, followed by appropriate antibiotic therapy, factors crucial in preventing rheumatic fever and other complications in children, including inflammation of the tonsils, lymph nodes, and middle ear. These measures also reduce spread of the illness to parents, siblings, classmates, and other close contacts. Avoiding treatment of viral illnesses with unnecessary antibiotics minimizes the potential adverse effects of antibiotic therapy and the likelihood that bacteria will develop antibiotic resistance.
The guidelines further advise against testing for group A strep by either rapid diagnostic testing or throat culture in children or adults with sore throats but additional symptoms of a viral infection, such as cough, hoarseness, mouth ulcers, and runny nose. Because group A strep infections are rare in children younger than 3 years, they should not get tested unless they have a risk factor, such an older sibling with a diagnosed strep infection. Finally, the recommendations advise against routine follow-up, post-treatment throat cultures and against routine screening of asymptomatic people in close contact with someone with a strep infection.
Patients, parents and health care providers alike should be aware of these guidelines and their intent to ensure appropriate testing, accurate diagnosis, and correct treatment of those suffering from a sore throat.
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NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.
Shulman, ST. et al. Clinical Practice Guideline for the Diagnosis and Management of Group A Streptococcal Pharyngitis: 2012 Update by the Infectious Diseases Society of America. Clin Infect Dis. First published online: September 9, 2012. Available online at http://cid.oxfordjournals.org/content/early/2012/09/06/cid.cis629.full through http://cid.oxfordjournals.org. Accessed September 2012.
Todd Neale. Group Updates Strep Throat guidelines. Medpage Today. Available online at http://www.medpagetoday.com/InfectiousDisease/GeneralInfectiousDisease/34696 through http://www.medpagetoday.com. Published September 11, 2012. Accessed September 18, 2012.