The diagnosis of most skin infections is made by the pattern of symptoms and physical exam findings.
However, it is not usually possible to know without cultur whether the infection is caused by the staph bacteria
or another bacteria, like group a beta-hemolytic streptococcus
(strep pyogenes). A culture of any weeping or abcess will help determine if staph is present.
Answer assisted by Samyukta Mullangi, Medical Student