Purpose We investigated balanoposthitis caused by Streptococcus pyogenes following sexual intercourse to reveal an efficient diagnosis and treatment.

Materials and Methods: Five male patients complaining of genital inflammation after sexual intercourse were diagnosed as balanoposthitis arising from Streptococcus pyogenes infection between 2008 and 2012. The clinical characteristics were retrospectively reviewed.

Results Three cases presented with marked pyoedema of the glans and foreskin mimicking gonococcal or chlamydial urethritis. The remaining two cases presented with papules, scabs and erosions without discharge, which were similar to candidiasis or genital herpes. All cases were diagnosed as balanoposthitis arising from Streptococcus pyogenes infection, which was confirmed by cultures of genital area. Two of them underwent biochemical testing of rapid antigen detection (StatCheck Strep A II^TM, Kainos Ltd., Japan) with bacterial culture examination, and identified as streptococcal balanoposthitis at the initial visit. Three cases were successfully treated with penicillin. Antibiotic susceptibility revealed that all cases were fluoroquinolone intermediate resistant patterns

Conclusion Streptococcal balanoposthitis has rarely been reported, and has not been recognised as a sexually transmitted infection. Because of common appearances and symptoms, it may have a higher prevalence than previously considered. These cases could be divided into two categories in terms of clinical characteristics,“discharge dominant type” and “eruption dominant type”. Rapid antigen detection of Streptococcus pyogenes should be attempted to use as first diagnostic tool for male genital inflammation for proper antibacterial therapy.