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Ask the expert!

In the last issue of Pediatric Views, we asked clinicians to send in questions they'd like answered by a Children's Hospital Boston expert. The response has been excellent. Below is the first in an ongoing Q&A series between Pediatric Views readers and experts.

Strep
Question: Historically, the preferred treatment of group A streptococcal pharyngitis has been 10 days of penicillin. Given the rising rates of antimicrobial resistance, does this still hold true? What is the role of cephalosporin or macrolide usage? What would your treatment algorithm be for recurrent strep? Please address the treatment for penicillin-allergic patients as well.

—Adam Strauss, MD
Westwood-Mansfield Pediatric Associates

Answer: No clinical group A strep isolate resistant to penicillin has been documented to date. Ampicillin or amoxicillin is often used instead of penicillin, but these agents offer no advantage.

For penicillin-allergic patients, erythromycin or another macrolide is the usual treatment, except when there is known to be a high prevalence of erythromycin resistance.

In treating patients for recurrent of group A strep (GAS) infection, a challenge is distinguishing between infection and colonization. Persistent or recurrent GAS pharyngitis can represent noncompliance with therapy, a new infection acquired from a close contact, or, less likely, treatment failure. In these patients, an additional course of penicillin or other agent is indicated. Throat culture with erythromycin or clindamycin sensitivity testing may be indicated if treatment with one of these agents fails.

For many patients who have recurrent symptoms of pharyngitis with positive GAS throat cultures or rapid antigen tests, the likely explanation is GAS colonization in the face of intermittent viral infections. While repeat throat culture or rapid antigen testing is not routinely recommended after treatment, retesting between pharyngitis episodes may be useful in diagnosing GAS colonization. Persistent positive tests in the absence of symptoms suggest that the patient is colonized. Patients with long-term GAS colonization do not have an increased risk for rheumatic fever, nor are they likely to be contagious, so treatment is not routinely recommended. When eradication of colonization is desired, clindamycin or penicillin plus rifampin may be more successful than penicillin alone.

—Catherine Lachenauer, MD
Assistant in Medicine, Division of Infectious Diseases www.childrenshospital.org/infectious

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