To detect and identify infectious agents such as streptococci and staphylococci bacterial strains blood tests and bacteria cultures can be used. Bacteria culture is suitable for identifying infectious agents in cases of severe<unk>  that do not respond well to treatment. DDx Infectious<unk>  should be differentiated from other conditions such as superficial thrombophlebitis (swelling is local to the affected vein), cat scratch (swellings feels hard to the touch), acute streptococcal hemolytic gangrene and necrotizing fasciitis (infected area crackles to the touch and the patient looks very ill).
Lymphangitis
Phlebitis
Thrombophlebitis
Deep vein thrombosis
Venous thrombosis
Phlegmon
Uveitis
Arteritis