最佳解答: Fifth disease
Fifth disease is also referred to as erythema infectiosum (meaning infectious redness) and as slapped cheek syndrome, slap face or slapped face.The name "fifth disease" is mainly historical: it is the fifth in the list of diseases causing childhood exanthemata (rashes). In 1975, its cause was discovered to be Parvovirus B19.
Toddler with "slapped cheek" characteristic of the fifth disease.
The bright red cheeks are a defining symptom of the infection in children (hence the name "slapped cheek disease"), but the rash will not extend over the bridge of the nose or around the mouth. In addition to the red cheeks, children often develop a red, lacy rash on the rest of the body, with the upper arms and legs being the most common locations. Patients are usually no longer infectious once the characteristic rash of this disease has appeared.
Teenagers and adults may present with a self-limited arthritis. Babies can turn purple.
The disease is usually mild, but it does have the ability to cause some serious problems: it is associated with spontaneous abortion in pregnant women, and with transient aplastic crisis in persons with chronic hemolytic anemia. Primary infection in the first trimester has been linked to hydrops fetalis. The rash can last a couple of weeks (some cases lasting for several months) and may itch.