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For further information, see CMDT 33-01: Streptococcal Infections

Key Features

  • Group A β-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

Clinical Findings

  • 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


  • 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


  • Parenteral antibiotics are indicated for patients with facial erysipelas or evidence of systemic infection

    • Penicillin, 2 million units every 4 hours intravenously, is the drug of choice

  • 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

Table 33–1.Treatment of common skin and soft tissue infections (SSTIs).

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