Clinical Perineal Streptococcal Infection in Children: Epidemiologic Features, Low Symptomatic Recurrence Rate after Treatment, and Risk Factors for Recurrence.

Objectives: To evaluate the epidemiology of perineal streptococcal infection and recurrence rates following amoxicillin treatment.

Study Design: We used laboratory logs in a single pediatric practice to identify patients 0-18 years of age with perineal cultures positive for group A Streptococcus (GAS) and reviewed their medical charts. We described epidemiologic features, determined recurrence rates following antibiotic treatment, and performed a case-control study to identify possible risk factors for recurrence in patients treated with amoxicillin.

Results: We found a perineal streptococcal infection rate of 4.6 per 10,000 patient encounters and a recurrence rate in 157 patients with perineal streptococcal infection of 12.4% after amoxicillin. In male patients, the predominant site of involvement was the perianal region (86%), and for female patients, the perivaginal area (62%). Nearly 80% of patients were 2-7 years of age (range 18 days-12.5 years). Perineal streptococcal infection and GAS pharyngitis followed a similar seasonal pattern of occurrence with 65% of perineal streptococcal infection occurring October through March. In patients with perineal streptococcal infection, 95% had a concomitant pharyngeal culture positive for GAS. Best predictive factors for recurrence after amoxicillin were longer duration of symptoms prior to diagnosis and having a sibling with perineal streptococcal infection at some time before or after the initial episode.

Conclusions: Following treatment with amoxicillin, we found a low recurrence rate of 12.4%. Amoxicillin can be expected to be reliable first-line therapy for perineal streptococcal infection.