Chickenpox in immunocompetent children is usually inconsequential but in HIV infected children can cause greater morbidity and mortality.
Clinical features
Patients present with vesicles which start as papules and eventually become crusted with distribution over face, trunks and limbs. With immunosuppression, vesicles may be large and extensive. Vesicles may also appear in crops over several days. Mucosal surfaces may also be involved. Systemic involvement in form of pneumonia, hepatitis and encephalitis may be seen with immunosuppression.
Diagnosis
Chickenpox is a clinical diagnosis. Giemsa staining (Tzanck smear) of cell scrapings from lesions may show multinucleated giant cells but is non-specific. Laboratory tests such as demonstration of VZV antigen in skin lesion, isolation of virus in culture from vesicle contents and a significant rise in VZV IgG antibody during convalescence of presence of VZV IgM antibody can help to confirm diagnosis.
Treatment
A child with chickenpox is infections till all the lesions have crusted. Hence, they should be isolated to avoid infecting other HIV infected children or adults. HIV infected children who have been exposed to chickenpox should be given varicella immunoglobulin within 96 hours of exposure [Dose: 1 vial/10 kg (max: 5 vials)].
HIV infected child with chickenpox, intravenous acyclovir (10 mg/kg/do IV tds) should be started as soon as initial lesions appear and continued till crusting of all lesions occur or till 7 days. Oral acyclovir (20 mg/kg/do PO qds) can be given in patients with a mild disease. Children who continue to develop lesions or whose lesions fail to heal may have acyclovir-resistant VZV and can be treated with IV Foscarnet (120 mg/kg/day in 3 divided doses) for 7 days.
Prophylaxis
Primary prophylaxis : HIV infected children who have no history of chickenpox or herpes zoster or are seronegative for varicella antibodies should be vaccinated with Varicella vaccine provided they are not immunosuppressed (have a CD4% more than 25%). Varicella vaccine is a live alternated vaccine and can be given after 12-15 months of age. It should not be given in immunosuppressed children because of rise of disseminated viral infection.
Secondary prophylaxis : No suppressive treatment is required post therapy.
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