The diagnosis of erythema infectiosum in children is established on the basis of the clinical findings of typical facial rash with absent or mild prodromal symptoms, followed by a reticulated rash over the body that waxes and wanes. The differential diagnosis includes measles, rubella, scarlet fever, enteroviral or adenoviral infection, infectious mononucleosis, scarlet fever, Kawasaki disease, systemic lupus erythematosus, serum sickness, and drug reaction.
There is no specific therapy. Routine supportive care includes maintaining adequate hydration and antipyretics. Transfusions may be required for transient aplastic crisis. Intrauterine transfusion has been performed for hydrops fetalis associated with fetal parvovirus B19 infection. Intravenous immunoglobulin may be used for immunocompromised persons with severe anemia or chronic infection.
The prognosis for erythema infectiosum is excellent. Fatalities associated with transient aplastic crisis are rare. Parvovirus B19 is not teratogenic, but in utero infection of fetal erythroid cells may result in fetal heart failure, hydrops fetalis, and fetal death. Of the approximately 50% of women of childbearing age susceptible to parvovirus B19 infection, 30% of exposed women develop infection, with 25% of exposed fetuses becoming infected and 10% of these culminating in fetal death.
The greatest risk is to pregnant women. Effective control measures are limited. Exclusion of affected children from school is not recommended, because children generally are not infectiousby the time the rash is present. Good handwashing and hygieneare practical measures that should help reduce transmission.
Chickenpox and zoster are caused by varicella-zoster virus (VZV), an enveloped, icosahedral, double-stranded DNA virus that is a member of the herpesvirus family. Humans are the only natural host. Chickenpox (varicella) is the manifestation of primary infection. VZV infects susceptible individuals via the conjunctivae or respiratory tract and replicates in the nasopharynx and upper respiratory tract. It disseminates by a primary viremia and infects regional lymph nodes, the liver, the spleen, and other organs. A secondary viremia follows, resulting in a cutaneous infection with the typical vesicular rash. After resolution of chickenpox, the virus persists in latent infection in the dorsal root ganglia cells. Zoster (shingles) is the manifestation of reactivated latent infection of endogenous VZV. Chickenpox is highly communicable in susceptible individuals, with a secondary attack rate of more than 90%. The period of communicability ranges from 2 days before to 7 days after the onset of the rash, when all lesions are crusted.
In the prevaccine era, the peak age of occurrence was 5 to 10 years, with peak seasonal infection in late winter and spring. In the postvaccine era, the incidence of varicella has declined in all age groups, with the peak incidence now in 10 to 14 year olds. Transmission is by direct contact, droplet, and air. Zoster is a recurrence of latent VZV and is transmitted by direct contact. Only 5% of cases of zoster occur in children younger than 15 years of age. The overall incidence of zoster (215 cases per 100,000 person-years) results in a cumulative lifetime incidence of approximately 10% to 20%, with 75% of cases occurring after 45 years of age. The incidence of zoster is increased in immunocompromised persons.
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