The objective of this practice guideline is to provide recommendations for the accurate diagnosis and optimal treatment of group A streptococcal pharyngitis in children and adults.
The desired outcomes are prevention of acute rheumatic fever, prevention of suppurative complications, improvement of clinical symptoms and signs, reduction in transmission of group A β-hemolyticstreptococci to close contacts of patients, and minimization of potential adverse effects of inappropriate antimicrobial therapy.
This statement is an update of the practice guideline published in 1997  and takes into account relevant research published since that time. A major substantive change is the acceptance of negative results of rapid antigen detection testing (RADT) for exclusion ofacute streptococcal pharyngitis, without the previously mandated confirmation with a negative culture result, provided certain criteria are met, as detailed below.
Acute pharyngitis is one of the most frequent illnesses for which pediatricians, internists, and other primary care physicians are consulted. Although the group A streptococcus is the most common bacterial cause of acutepharyngitis, only a small percentage of patients with this condition are infected by group A streptococci. Moreover, group A streptococcal pharyngitis is the only commonly occurring form of acute pharyngitis for which antibiotic therapy is definitely indicated. Therefore, for a patient with acute pharyngitis, the clinical decision that usually needs to be made is whether the pharyngitis isattributable to group A streptococci.
The signs and symptoms of group A streptococcal and other (most frequently viral) pharyngitides overlap broadly. Therefore, unless the physician is able with confidence to exclude the diagnosis of streptococcal pharyngitis on epidemiological and clinical grounds, a laboratory test should be done to determine whether group A streptococci are present in the pharynx. Thetest may be either culture of a throat swab specimen or an RADT, which detects the presence of group A streptococcal carbohydrate on a throat swab. A positive result of throat culture or RADT for a patient with signs and symptoms of acute pharyngitis is considered, for clinical purposes, to establish the diagnosis of "strep throat." However, because some RADTs appear to be considerably lesssensitive than is culture of a throat swab specimen, a negative RADT result for a child or adolescent should be confirmed by performance of a throat culture, unless the physician has ascertained in his or her practice that the RADT being used is comparable in sensitivity to a throat culture. Because of the epidemiological features of acute pharyngitis in adults (e.g., low incidence of streptococcalinfection and extremely low risk of rheumatic fever), diagnosis of this infection in adults on the basis of the results of an RADT, without confirmation of negative RADT results by negative results of culture, is an acceptable alternative to diagnosis on the basis of throat culture results ( figure 1 ). The generally high specificity of RADTs should minimize over-prescription of antimicrobials fortreatment of adults.
Figure 1. Diagnosis and management of acute pharyngitis. The algorithm applies to uncomplicated cases of acute pharyngitis. Additional diagnostic and therapeutic measures may be necessary for patients with suppurative complications (e.g., peritonsillar abscess or cervical lymphadenitis) or infection with uncommon pharyngeal bacterial pathogens (e.g., Corynebacteriumdiphtheriae, Neisseria gonorrhoeae ) is suspected. *See the discussion in Diagnosis of Group A Streptococcal Pharyngitis. Neg., negative result; pos., positive result.
Patients with acute streptococcal pharyngitis should receive therapy with an antimicrobial agent in a dose and for a duration that is likely to eradicate the infecting organism from the pharynx. A number of antibiotics have been...