Generalized petechial rashes in children during a parvovirus B19 outbreak.

OBJECTIVES: Human parvovirus B19 infection is associated not only with erythema infectiosum (fifth disease) but also, rarely, with purpuric or petechial rashes. Most reports of these atypical rashes describe sporadic cases with skin lesions that have distinctively focal distributions. During a community outbreak of fifth disease, we investigated a cluster of illnesses in children with generalized petechial rashes to determine whether parvovirus was the causative agent and, if so, to describe more fully the clinical spectrum of petechial rashes that are associated with this virus. METHODS: Systematic evaluation was conducted by general pediatricians of children with petechial rashes for evidence of acute parvovirus infection. RESULTS: During the outbreak, acute parvovirus infection was confirmed in 13 (76%) of 17 children who were evaluated for petechial rash. Confirmed case patients typically had mild constitutional symptoms, and most (11 [85%] of 13) had fever. Petechiae were typically dense and widely distributed; sometimes accentuated in the distal extremities, axillae, or groin; and usually absent from the head/neck. Most case patients had leukopenia, and several had thrombocytopenia. Parvovirus immunoglobulin M was detected in 8 (73%) of 11 acute-phase serum specimens, and immunoglobulin G was detectable only in convalescent specimens. Parvovirus DNA was detected in all 7 tested serum specimens, including 2 acute-phase specimens that were immunoglobulin M-negative. All case patients had brief, uncomplicated illnesses, but 6 were briefly hospitalized and 1 underwent a bone marrow examination. Two case patients developed erythema infectiosum during convalescence. CONCLUSIONS: During an outbreak of fifth disease, parvovirus proved to be a common cause of petechial rash in children, and this rash was typically more generalized than described in case reports. Associated clinical features, hematologic abnormalities, and serologic test results are consistent with a viremia-associated illness that is distinct from and occasionally followed by erythema infectiosum.