Clinical Manifestations of Group A beta-Hemolytic Streptococcal Pharyngits and Usefulness of Rapid Antigen Test

ABSTRACT

PURPOSE: Accurate diagnosis of group A streptococcal(GAS) pharyngitis and appropriate antimicrobial therapy are important, particularly to prevent nonsuppurative sequelae and to reduce the improper use of antibiotics. Because the clinical presentation of pharyngitis does not reliably predict the etiologic agent, when GAS infection is suspected, diagnosis should be based on the result of a throat swab culture or antigen-detection test with culture back-up. METHODS: We reviewed retrospectively the medical records of children diagnosed as GAS pharyngitis by throat swab culture from Jan. 1995 to Jul. 2000. Since Nov. 1998, specimens were also tested with the Abbott's Testpack+plus Strep A Kit. RESULTS: 121 patients were confirmed as GAS pharyngitis by throat culture. GAS pharyngitis predominantly occurred from 3 to 7 years of age with the peak incidence at 4 and 5 years of age. The disease was more frequent in late fall, winter and spring. Clinical manifestations were as follows; fever(89.9%), abnormal pharynx(94.3%), of which exudate in 33.6%, sore throat(85.3%), headache(78.1%), cervical lymphadenopathy(67.5%), abdominal pain(64.3%), and nausea or vomiting (55.0%). The sensitivity and specificity of rapid antigen test compared to throat culture were 96.4% and 95%, respectively. CONCLUSION: GAS pharyngitis occurred every year, and more frequently in late fall, winter and spring. It occurred with the greatest frequency in preschool children. The rapid antigen test can be a basis for clinicians to decide how to treat their patients before the culture results are proven, and can be helpful to judicious use of antibiotics as well.