Signs and Symptoms of Fifth Disease
The incubation period for fifth disease ranges from 1 to 2 weeks. Elevated quantities of the virus are found in the blood and secretions for about 1 to 2 weeks after exposure. During this time, low-grade fever and malaise may be present.
About 2 weeks after exposure, a characteristic rash appears, in three stages. First a "slapped cheek", or "sunburned" appearance on the child's face occurs.
Second, pink, slightly elevated bumps appear on the arms and legs. Finally, after several days, the rash begins to fade, and an overall lacy or marble-like pattern occurs. This last phase of the rash is highly diagnostic of fifth disease. The lacy rash typically resolves in 1 1/2 weeks but can persist more than 3 weeks. After apparent resolution, it may resurface, especially during hot weather. There are some reports of itching.
In adults, especially women, sudden joint pain is the primary symptom, affecting the hands, wrists, feet, ankles, and knees. While it usually resolves quickly, it can persist or recur for months. Men more often present with flu-like symptoms. Sometimes fatigue and malaise can linger for weeks after the infection. Itching can occur as well, even without a rash.
Rarely, a "gloves and socks" syndrome can be seen in teenagers and adults. It presents with redness and swelling of the hands and feet as well as petechiae (pe-TE-ke-ay), minute red spots in the skin caused by blood leaking from the capillaries. This eruption resolves within 2 weeks.
Fifth Disease Complications
Parvovirus B19 can cause massive decreased blood cell production, especially in people with a history of decreased production or increased destruction of blood cells. Fatigue, worsening anemia, and paleness can be seen. A blood transfusion may be needed, if the red blood cell count drops too low. Shortly after, the transfusion, bone marrow produces more red blood cells and recovery occurs.
Infected pregnant women with no prior B19 infection and no immunity to the virus are at risk for complications. The risk of infection following exposure is less than 10 percent. Most fetuses are not affected, however miscarriage, severe anemia, and death of the fetus have been reported. Parvovirus B19 is not a common cause of birth defects.