Fifth disease Fifth disease Fifth disease, more commonly known as erythema infectiosum, is an infection caused by a virus called human parvovirus B-19, which mostly affects children. It is characterized by a reddish rash, usually lasting no more than 10 days. Later, a rash develops over the trunk.
Fever is rare.
No treatment is necessary, as fifth disease clears up by itself. The child need not stay home from school. Pregnant women who have not previously had the infection may be susceptible to it and the virus may cause fetal abnormalities.