Parvovirus B19

Fifth disease (erythema infectiosum) Slapped cheek

Epidemiology

It is common in immunosuppressed patients: people with HIV infection, receiving chemotherapy, transplant patients.

Incubation lasts 4-14 days. The infectious period precedes the onset of rash.

Specifically infects and kills erythroid progenitor cells, binding to the P antigen on erythroblasts.

The first 7-10 days are characterized by a febrile, flu-like illness.

A rash appears on days 10-17.

distinct 'slapped cheek' rash of raised maculopapules, sparing the area around the mouth
may be pruritic and appear on the extensor surfaces, trunk, neck and buttocks
lacy pink rash of extremities
resolves within a week, but can return with exposure to heat
may cause congenital abnormalities (ie cardiac) if infection occurs during pregnancy

In the absence of an effective antibody response, infection can cause a pure red cell aplasia, leading to aplastic anemia.

In adults, symptoms can also include:

Fetal infection can cause severe anemia, congestive heart failure, and hydrops fetalis.

Treatment is supportive.

Blood transfusions can be given to those with aplastic anemia.