Erysipelas is most commonly caused by which organism?

Erysipelas is a superficial skin infection involving the upper dermis and superficial lymphatics. It is almost exclusively caused by Group A beta-hemolytic Streptococcus (Streptococcus pyogenes). Clinically, it presents with a sharply demarcated, raised, bright red ('fiery') plaque with well-defined borders (distinguishing it from cellulitis, which has poorly defined borders). Common sites are the face and lower extremities. Systemic symptoms (fever, chills) are typical. Treatment is penicillin or amoxicillin. Both 'beta-hemolytic streptococci' and 'Group A Streptococcus' are correct descriptions of the same organism — Group A Streptococcus IS beta-hemolytic.