Infectious Diseases: Varicella-Zoster Infections

Varicella-Zoster Infections

CLINICAL MANIFESTATIONS:
Primary infection results in varicella (chickenpox), manifesting as a generalized, pruritic, vesicular rash typically consisting of 250 to 500 lesions in varying stages of development and resolution (crusting), mild fever, and other systemic symptoms. Complications include bacterial superinfection of skin lesions, pneumonia, central nervous system involvement (acute cerebellar ataxia, encephalitis), thrombocytopenia, and other rare complications such as glomerulonephritis, arthritis, and hepatitis. Varicella tends to be more severe in adolescents and adults than in young children. Reye syndrome can follow cases of chickenpox, although the incidence of Reye syndrome has decreased dramatically with decreased use of salicylates during varicella or influenza-like illnesses. In immunocompromised children, progressive severe varicella characterized by continuing eruption of lesions and high fever persisting into the second week of illness as well as encephalitis, hepatitis, and pneumonia can develop. Hemorrhagic varicella is more common among immunocompromised patients than immunocompetent hosts. Pneumonia is relatively less common among immunocompetent children but is the most common complication in adults. In children with human immunodeficiency virus (HIV) infection, recurrent varicella or disseminated herpes zoster can develop. Severe and even fatal varicella has been reported in otherwise healthy children receiving intermittent courses of high-dose corticosteroids (>2 mg/kg of prednisone or equivalent) for treatment of asthma and other illnesses. The risk especially is high when corticosteroids are given during the incubation period for chickenpox.
The virus establishes latency in the dorsal root ganglia during primary infection. Reactivation results in herpes zoster ("shingles"). Grouped vesicular lesions appear in the distribution of 1 to 3 sensory dermatomes, sometimes accompanied by pain localized to the area. Postherpetic neuralgia, which may last for weeks to months, is defined . . . [Go to Full Text]

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