Isolated anogenital infection secondary to group A Streptococcus in prepubertal child

Abstract

The vulva, as the external portion of the female reproductive system, has specific anatomical and physiological features in prepubertal girls that predispose it to infections. In this population, the mucosa is thinner, non-cornified, and alkaline due to low estrogen levels and the absence of protective bacterial flora. These factors, combined with close proximity to the rectum and behavioral habits such as poor hygiene or hand-to-genital contact, increase susceptibility to infection. While a wide range of pathogens can affect the vulvar region, infections caused by Streptococcus pyogenes remain uncommon but clinically significant, especially in young children. A three-year-old girl presented with vulvar redness and discomfort, without systemic symptoms such as fever or respiratory complaints. Examination revealed bright red erythema localized to the vulvar and perianal areas, but no ulceration or discharge. Laboratory evaluation, including a Gram stain and bacterial culture, confirmed the presence of Streptococcus pyogenes. The organism was identified using mass spectrometry and found to be sensitive to multiple antibiotics, including penicillin and cephalosporins. The patient was treated with a seven-day course of amoxicillin, resulting in rapid improvement and full resolution of symptoms. Follow-up confirmed no recurrence. This case highlights that Streptococcus pyogenes, although more commonly associated with throat and skin infections, can present as localized vulvitis and perianal erythema in young girls without systemic signs. Prompt recognition, appropriate specimen collection, and the use of modern diagnostic tools can lead to early diagnosis and effective treatment.