Erythema Infectiosum
Merck Manual (18th Edition), 2005 See article at www.merck.com
[len:46881, cleaned:] Erythema Infectiosum: Infections in Infants and Children: Merck Manual Professional Recent Searches In This Topic Section Subject Topics · · · · Erythema Infectiosum (Fifth Disease; Parvovirus B19 Infection) Erythema infectiosum, acute infection with parvovirus B19, causes mild constitutional symptoms and a blotchy or maculopapular rash beginning on the cheeks and spreading primarily to exposed extremities. Diagnosis is clinical, and treatment is generally not needed. The disease is caused by human parvovirus B19. It occurs mostly during the spring, commonly causing localized outbreaks every few years among children (particularly those 5 to 7 yr). Spread appears to be by respiratory droplets, with high rates of secondary infection among household contacts; infection can occur without symptoms or signs. Parvovirus B19 causes transient suppression of erythropoiesis that is mild and asymptomatic except in patients with underlying hemoglobinopathies (eg, sickle cell disease) or other RBC disorders (eg, hereditary spherocytosis), who may develop transient aplastic crisis. Symptoms and Signs The incubation period is 4 to 14 days. Typical initial manifestations are nonspecific flu-like symptoms (eg, low-grade fever, slight malaise). Several days later, an indurated, confluent erythema appears over the cheeks (“slapped-cheek” appearance) and a symmetric rash appears that is most prominent on the arms, legs, and trunk, usually sparing the palms and soles. The rash is maculopapular, tending toward confluence; it forms reticular or lacy patterns of slightly raised, blotchy areas with central clearing, usually most prominent on exposed areas. The rash, and the entire illness, generally lasts 5 to 10 days. However, the rash may recur for several weeks, exacerbated by sunlight, exercise, heat, fever, or emotional stress. Mild joint pain and swelling (nonerosive arthritis) that may persist or recur for weeks to months sometimes occurs in adults. Immunocompromised patients can develop protracted viremia (lasting 10 to 12 days), leading to severe anemia (chronic pure RBC aplasia). Erythema infectiosum can be transmitted transplacentally, sometimes resulting in stillbirth or severe fetal anemia with widespread edema (hydrops fetalis). However, about 1 ⁄ 2 of pregnant women are immune because of previous infection. The risk of fetal death is 5 to 9% after maternal infection, with risk greatest during the 2nd trimester. Diagnosis and Treatment The appearance and pattern of spread of the rash are the only diagnostic features; however, some enteroviruses may produce similar rashes. Rubella can be ruled out by serologic testing; an exposure history is also helpful. Serologic testing is not required in otherwise healthy children; however, in children with transient aplastic crisis or adults with arthropathy, the presence of IgM-specific antibody to parvovirus B19 in the late acute or early convalescent phase strongly supports the diagnosis. Parvovirus B19 viremia also can be detected by immunoprecipitation or molecular techniques, which are generally used for patients with transient aplastic crisis, immunocompromised patients with chronic pure RBC aplasia, and infants with hydrops fetalis or congenital infection. Only symptomatic treatment is needed. IV immune globulin has been used to curtail viremia and increase erythropoiesis in immunocompromised patients with chronic RBC aplasia. Last full review/revision November 2005 Content last modified November 2005 Previous: Next: Audio Figures Photographs Sidebars Tables Videos
