A live attenuated varicella vaccine—two doses for all children—is recommended. The first dose should be administered at age 12 to 15 months and the second dose at 4 to 6 years. Varicella vaccine is 85% effective in preventing any disease and 97% effective in preventing moderately severe and severe disease. Transmission of vaccine virus from a healthy vaccinated individual is rare but possible.
Passive immunity can be provided by VZIG, which is indicated within 96 hours of exposure for susceptible individuals at increased risk for severe illness. Administration of VZIG does not eliminate the possibility of disease in recipients and prolongs the incubation period up to 28 days.
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Nonbullous or crusted impetigo is caused most often by Staphylococcus aureus and occasionally by group A streptococcus. Itbegins as a single erythematous papulovesicle that progresses to one or many honey-colored, crusted lesions weeping serous drainage. Bullous impetigo accounts for approximately 10%of all impetigo. The skin lesions are thin-walled (0.5 to 3 cm)bullae with erythematous margins resembling second-degreeburns and are associated with S. aureus phage type 71. Impetigo most frequently occurs on the face, around the nares andmouth, and on the extremities. Fever is uncommon. The diagnosis usually is established by the clinical appearance alone.
Recommended treatment for nonbullous impetigo is topical 2% mupirocin or oral antistaphylococcal antibiotics. Extensive or disseminated lesions, bullous impetigo, lesions around the eyes, or lesions otherwise not amenable to topical therapy are best treated with oral antibiotics. Streptococcal impetigo is associated with increased risk of postinfectious glomerulonephritis but not acute rheumatic fever (see Chapter 163). Antibiotic treatment does not decrease the risk of postinfectious glomerulonephritis but decreases possible spread of nephritogenic strains to close contacts. Children with impetigo should remain out of school or day care until 24 hours of antibiotic therapy have been completed.
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Cellulitis is infection involving the subcutaneous tissues and the dermis and is usually caused by S. aureus or groupA streptococci. Cellulitis typically presents with indurated, warm, and erythematous macules with indistinct borders that expand rapidly. Additional manifestations commonly include fever, lymphangitis, and regional lymphadenitis. Erysipelasis a superficial variant of cellulitis usually caused by group A streptococcus that involves the dermis only. The rapidly advancing lesions are tender, bright red in appearance, and have sharp margins. The patients may appear toxic. Blood cultures are recommended for erysipelas. Empirical antibiotic treatment for cellulitis is recommended with a first-generation cephalosporin unless the local S. aureus methicillin-resistance rate is high, in which case alternatives include clindamycin or trimethoprim-sulfamethoxazole (although this agent has poor group A streptococcal activity). Many patients may be managed with oral antibiotics and close follow-up; hospitalization and intravenous antibiotics are recommended for erysipelas and cellulitis of the face, hands, feet, or perineum; those with lymphangitis; and those not responding to outpatient therapy.