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For further information, see CMDT PART 6-33: INFECTIOUS ERYTHEMAS
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Essentials of Diagnosis
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Edematous, expanding, erythematous, warm plaque with or without vesicles or bullae
Lower leg is frequently involved
Pain, chills, and fever are commonly present
Septicemia may develop
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General Considerations
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Usually due to gram-positive cocci, though gram-negative rods or even fungi can produce similar picture
The major portal of entry for lower leg cellulitis is toe web tinea pedis with fissuring of the skin at this site
Erysipelas is a superficial form of cellulitis that occurs classically on the cheek, caused by β-hemolytic streptococci (see Erysipelas)
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Lesion begins as a small batch and expands over hours
Edematous, expanding, erythematous, warm plaque with or without vesicles or bullae
Pain at the lesion, malaise, chills, and moderate fever
Usually on the lower leg
Lymphangitis and lymphadenopathy may be present
Progressive chills, fever, and malaise
Septicemia and septic shock may develop
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Differential Diagnosis
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Attempts to isolate the responsible organism by injecting and then aspirating saline are successful in 20% of cases
Leukocytosis and an increased sedimentation rate are almost invariably present but are not specific
Blood cultures may be positive
Skin biopsy is particularly helpful in an immunocompromised patient whose cellulitis may be due to an uncommon organism
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Diagnostic Procedures
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Intravenous or parenteral antibiotics effective against group A β-hemolytic streptococci and staphylococci may be required for the first 24–48 hours
Dicloxacillin or cephalexin, 250–500 mg four times daily orally for 5–10 days, is usually adequate for mild cases or following initial parenteral therapy
In patients in whom intravenous treatment is not instituted, the first dose of oral antibiotic can be doubled to achieve rapid high blood levels
Oral penicillin 250 mg twice daily or oral erythromycin 250–500 mg twice daily can decrease the risk of recurrence in patients with recurrent lower leg cellulitis (three to four ...