Predictive value of clinical features in differentiating group A beta-hemolytic streptococcal pharyngitis in children.

Identifying children with acute pharyngitis caused by group A beta-hemolytic Streptococcus (GABHS) is an important task for pediatricians. This study examined the value of certain clinical symptoms and signs in predicting a positive culture result. A total of 442 children who presented at the outpatient department with pharyngeal erythema were enrolled. The clinical features of patients with positive throat cultures for GABHS were compared to those with negative culture results. Throat cultures were positive for GABHS in 120 (27%) patients. Patients aged between 5 and 10 years had a higher prevalence of GABHS pharyngitis. Significant differences between the groups with and without GABHS pharyngitis were noted for the presence of sore throat (p < 0.001), tonsillar swelling (p < 0.001), anterior cervical adenopathy (p = 0.004), and scarlatiniform rash (p < 0.001), but not for the presence of fever, cough, rhinorrhea, abdominal pain, headache, tonsillar exudate, or palatal petechiae. Despite these strong associations, none of these symptoms or signs had both high sensitivity and specificity, and the positive predictive values of these individual findings were never greater than 50%. The results indicate that diagnosis based on clinical grounds alone is unreliable although there are certain individual symptoms and signs that are associated with GABHS pharyngitis. These symptoms and signs may be helpful in modifying estimates of probability of infection with GABHS. Throat cultures in suspected patients remain mandatory.