Fifth disease (erythema infectiosum) is a contagious and usually mild viral illness that is common in children. Early symptoms of fifth disease resemble the flu; these are followed by a characteristic rash on the face that looks like slapped cheeks and a lacy pink rash on the backs of the arms and legs, torso, and buttocks.

This illness is most contagious the week before the rash appears. Once the rash has developed, the child usually is no longer considered contagious. The rash may come and go for several weeks in response to changes in temperature and sunlight.

To treat fifth disease, keep the child comfortable and watch for signs of a more serious illness, such as a fever higher than 102°F (38.9°C) or other signs that the child may be very sick.

Fifth disease, although usually a mild illness in children, poses a slight risk to developing fetuses. Pregnant women should avoid being exposed to the disease if possible. If a pregnant woman is exposed to a child who has fifth disease, or develops a rash like that caused by fifth disease, she should contact her health professional.