Snapshot An 18-year-old man presents with a painful rash on his upper arm. He reports a recent mosquito bite in the same area three weeks ago. Since then, the area has become red, painful, and hot. On physical exam, his physician notes a well-demarcated raised area that is bright pink and hot to the touch. He is sent home on penicillin. Introduction Clinical definition login to view 6 more bullets Pathogenesis login to view 1 more bullet Epidemiology Demographics login to view 1 more bullet Risk factors login to view 7 more bullets Etiology S. pyogenes login to view 1 more bullet S. aureus Presentation Symptoms login to view 1 more bullet Physical exam login to view 4 more bullets Studies Labs login to view 1 more bullet Diagnosed clinically Differential Cellulitis login to view 2 more bullets Treatment Conservative login to view 3 more bullets Medical login to view 7 more bullets Complications Sepsis Prognosis Recurs in 10-40% of cases