Erythema infectiosum (fifth disease)
Erythema infectiosum (fifth disease) is the classic biphasic exanthem of parvovirus B19 infection in children, defined by a slapped-cheek facial rash followed by a lacy reticular rash on the extremities and trunk. It is usually clinically diagnosed and self-limited, but the same virus can trigger aplastic crisis in patients with hemolytic disease and fetal hydrops in pregnancy, so recognizing at-risk exposures drives management.
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What this article covers
- Overview
A biphasic childhood exanthem caused by parvovirus B19: erythema infectiosum, or fifth disease, presents with a distinctive slapped-cheek facial rash followed by a lacy, reticular rash on the trunk…
- Epidemiology
A common childhood infection, transmitted person-to-person, typically affecting school-age children, with outbreaks common in daycare and classroom settings.
- Risk factors
Household or classroom exposure to an infected child during the pre-rash viremic phase, since transmission occurs before the rash is recognized.
- Pathophysiology
Parvovirus B19 is a single-stranded DNA virus that directly infects erythrocyte precursors in the bone marrow, producing transient reticulocytopenia during acute infection.
- Clinical features
The illness is biphasic, and the pattern itself is diagnostic: stage one is an abrupt "slapped-cheek" erythema of the face, with circumoral pallor, typically with little or no preceding fever.
- Differential diagnosis
Roseola infantum (sixth disease): high fever for 3 to 5 days that resolves before a nonpruritic, blanchable truncal rash appears, the reverse of fifth disease's rash-without-preceding-fever pattern, and without the slapped-cheek stage.
- Diagnosis
The biphasic clinical pattern, slapped-cheek facial erythema followed by a lacy reticular rash on the extremities and trunk in an appropriately exposed child, is itself diagnostic of typical erythema…
- Management
First, for the typical immunocompetent child or adult with erythema infectiosum, treat symptomatically: acetaminophen 10 to 15 mg/kg PO every 4 to 6 hours as needed for fever or discomfort (maximum 5…
- Complications
Aplastic crisis in a patient with an underlying hemolytic anemia or another cause of increased red cell turnover is the most acute, life-threatening complication.
- Prognosis
The typical childhood exanthem is self-limited and resolves without sequelae over 1 to 3 weeks, though the rash can recur transiently with heat, sun exposure, or exercise for a period afterward.
- Prevention
No vaccine exists; prevention relies on standard infection-control precautions during the contagious pre-rash phase in a household or classroom outbreak.
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Related articles
- Parvovirus B19 infection
Parvovirus B19 is a single-stranded DNA virus that infects erythrocyte precursors in the bone marrow, producing transient reticulocytopenia that is usually silent but becomes clinically important in three settings: symmetric small-joint arthropathy in adults, aplastic crisis in patients with a hemolytic anemia, and chronic pure red cell aplasia or fetal hydrops when the host cannot clear the virus. Serology confirms infection in the immunocompetent host, while bone marrow pronormoblasts or PCR are needed in the immunosuppressed.
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