Parvovirus B19 (Fifth Disease)

In this episode, we tackle the clinical mischief of Parvovirus B19, a common viral infection with a surprisingly wide range of manifestations—from the classic “slapped cheek” rash of erythema infectiosum to aplastic crises in children with hemolytic anemias and fetal hydrops in pregnant contacts. We’ll break down the virology, epidemiology, clinical presentation, and complications of Parvovirus B19. You’ll also learn how to manage exposures in the emergency department, especially when the child has a pregnant caregiver, and why isolation isn’t always necessary once the rash shows up.

Learning Objectives

• Describe the classic and atypical clinical presentations of Parvovirus B19 infection in pediatric patients, including erythema infectiosum, arthropathy, transient aplastic crisis, and chronic anemia in immunocompromised hosts.
• Understand the epidemiology and transmission timeline of Parvovirus B19, especially its seasonal peaks and viral shedding period.
• Recognize key diagnostic features that help differentiate Parvovirus B19 from other viral exanthems and systemic illnesses.
• Formulate an evidence-based management plan for patients with suspected or confirmed Parvovirus B19, including those with underlying hemolytic disease or immunocompromise.
• Counsel families and caregivers—including pregnant household contacts—on the risks, exposures, and infection control considerations related to Parvovirus B19.

Connect with Brad Sobolewski

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• Instagram: Brad Sobolewski
• Mastodon: @[e-mail]

References

Jordan, Jeanne A. “Treatment and Prevention of Parvovirus B19 Infection.” UpToDate, Jun. 14, 2024. https://www.uptodate.com/contents/treatment-and-prevention-of-parvovirus-b19-infection

Edwards, Morven S. “Clinical Manifestations and Diagnosis of Parvovirus B19 Infection.” UpToDate, Jun. 14, 2024. https://www.uptodate.com/contents/clinical-manifestations-and-diagnosis-of-parvovirus-b19-infection

Macri, Angela, and Crane, Jonathan S. “Parvoviruses.” StatPearls, NCBI Bookshelf, Jun. 28, 2023. https://www.ncbi.nlm.nih.gov/books/NBK482245/

Kostolansky, Sean, and Waymack, James R. “Erythema Infectiosum.” StatPearls, NCBI Bookshelf, Jul. 31, 2023. https://www.ncbi.nlm.nih.gov/books/NBK513309/

“Parvovirus B19 Infection and Pregnancy.” Centers for Disease Control and Prevention. https://www.cdc.gov/parvovirusb19/pregnancy.html

Transcript

Note: This transcript was partially completed with the use of the Descript AI and the Chat GPT 4o AI

Welcome to PEMCurrents, the Pediatric Emergency Medicine Podcast. As always, I’m your host, Brad Sobolewski, and today we are covering Parvovirus B19—a common but clinically diverse viral infection that you will definitely encounter in pediatrics, and not just in the form of a rash. Parvovirus B19 is best known for causing fifth disease, but in certain patients it can lead to some serious complications like aplastic crises, fetal hydrops, or chronic anemia.

So as you can see, this virus does a lot of stuff. But what is it? Well, let’s get nerdy. It is a non-enveloped, single-stranded DNA virus in the Parvoviridae family. There are some forms of parvo that infect other mammals, but Parvovirus B19 is only for humans, and it loves erythroid progenitor cells. It was discovered by accident back in 1975, so a little bit before I was born, and it was labeled B19 because of the sample number in a Hepatitis B screening panel. Since then it has been identified as the cause of several syndromes. I’ll go over those as we move along here.

Parvovirus B19 is spread via respiratory droplets, much less commonly by blood products or vertical transmission. The incubation period is typically four to fourteen days. Viremia peaks at days five through ten after exposure, and that’s when the patient is most contagious. The classic rash and joint symptoms appear later, and at that point, the patient is actually no longer infectious. So that detail’s key—because when a kid shows up with a slapped cheeks rash, you no longer need to isolate them.

So the classic presentation that’s on every board exam ever is called erythema infectiosum, or fifth disease. This is the most well-known manifestation, seen primarily in school-aged children, especially in the spring and early summer. Again, it’s also known as fifth disease—this is one of the six classic childhood exanthems. These are a group of viral rash-causing ill