Fifth disease
Fifth disease is one of several possible manifestations of infection by parvovirus B19. Fifth disease is more common in children.

Fifth disease starts with a low-grade fever, headache, rash, and cold-like symptoms, such as a runny or stuffy nose. These symptoms pass, then a few days later, the rash appears. The bright red rash most commonly appears in the face, particularly the cheeks. (hence the name "slapped cheek disease"). In addition to red cheeks, children often develop a red, lacy rash on the rest of the body, with the upper arms, torso, and legs being the most common locations.

The disease is usually mild, but in pregnant women, infection in the first trimester has been linked to hydrops fetalis, causing spontaneous miscarriage.

No specific treatment is required as it usually improves over time.

  • 16-month-old with Fifth disease ― Both cheeks turn red, as if being slapped, and maculopapular rashes appear on the body.
  • Erythema on both cheeks.
  • The body may also be accompanied by a reticulated rash.
  • This is a characteristic bilateral slapped cheeks rash caused by B19 virus infection.
References Fifth disease (parvovirus B19) 35951969 
Fifth disease (erythema infectiosum) is a viral infection caused by human parvovirus B19. It is more common in children than adults and usually affects children ages 4 to 14. The disease often starts with mild fever, headache, sore throat, and other flu-like symptoms. Children can also develop a bright red rash on the face that looks like “slapped cheeks”, along with a lacy or bumpy rash on the body, arms, and legs. In adults, joint aches are a common symptom. Rash and joint symptoms may develop several weeks after infection. About 20 to 30% of adults who are infected with parvovirus B19 will not have symptoms.
 Exposure to fifth disease in pregnancy 20008596 
The rate of vertical transmission during maternal parvovirus B19 infection is estimated at 33%, with fetal complications occurring in 3% of infected women. Fetal complications comprising hemolysis, anemia, and nonimmune hydrops fetalis and fetal loss are more frequent when maternal infection occurs before 20 weeks of gestation. The first step in the management of this patient would be to obtain immunoglobulin (Ig) M and IgG titres against parvovirus to evaluate if the patient has had previous immunity against the disease. If results are negative for IgG but positive for IgM (ie, primary infection), this patient would need close obstetrical monitoring for the following weeks, including serial ultrasounds to rule out fetal anemia and hydrops fetalis.