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For further information, see CMDT 33-01: Streptococcal Infections
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Group A beta-hemolytic streptococci are not normal skin flora
Usually result from colonization of normal skin by contact with other infected individuals or by preceding streptococcal respiratory infection
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Impetigo
Focal, vesicular, pustular lesion with a thick, amber-colored crust that has a "stuck-on" appearance
Erysipelas
Painful superficial cellulitis that frequently involves the face
Indurated, slightly elevated, and well demarcated from the surrounding normal skin
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Cultures obtained from skin are usually negative unless there is a wound, pustule, or impetigo, but if positive can help to exclude nafcillin-resistant streptococci
Blood cultures are occasionally positive
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Parenteral antibiotics are indicated for patients with facial erysipelas or evidence of systemic infection
For severely ill patients or those who have risk factors for staphylococcal infection (eg, injection drug use, wound infection, diabetes) reasonable choices for initial therapy include
Nafcillin, 1–2 g every 4–6 hours intravenously, or
Cefazolin, 1 g intravenously or intramuscularly every 8 hours
In the patient at risk for methicillin-resistant S aureus infection or with a serious penicillin allergy (ie, anaphylaxis), vancomycin, 1000 mg every 12 hours intravenously, or daptomycin, 4 mg/kg intravenously daily, should be used (Table 33–1)
Patients who do not require parenteral therapy may be treated with amoxicillin, 500 mg three times daily or 875 mg twice daily orally for 7–10 days
A first-generation oral cephalosporin, eg, cephalexin, 500 mg four times daily, or clindamycin, 300 mg orally three times daily, is an alternative to amoxicillin
Maintenance therapy with penicillin, 250 mg orally twice daily (for at least 1 year), can reduce the likelihood of relapse of recurrent cellulitis in the leg
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