Background: Most of the world's children live in regions where laboratory facilities are not available. In these regions, clinical prediction rules can be useful to guide clinicians' decisions on antibiotic therapy for streptococcal pharyngitis, and to reduce routine presumptive antibiotic therapy for all pharyngitis.
Methods: Prospective cohort study to assess diagnostic signs and develop a prediction rule. Bivariate and multivariate analyses were used to develop clinical rules. Participants were 410 children in Cairo, Egypt, aged from 2 to 12 y, presenting with complaint of sore throat and whose parents provided consent. Main outcome measures included presence of signs and symptoms, and positive group A beta hemolytic streptococcal (GABHS) culture.
Results: 101 (24.6%) children had positive GABHS culture. Pharyngeal exudate, tender or enlarged anterior cervical lymph nodes, season, absence of rash, or cough or rhinitis were associated with positive culture in bivariate and multivariate analyses. Three variables (enlarged nodes, no rash, no rhinitis), when used in a cumulative score, showed 92% sensitivity and 38% specificity in these children.
Conclusions: The proposed three-variable clinical prediction rule for GABHS may be useful when diagnostic laboratories are not available. In this setting, the rule identified more than 90% of true cases. Compared to universal treatment of all pharyngitis, the rule will reduce antibiotic use in GABHS-negative cases by about 40%.