An acute disease of infants, caused by herpesvirus 6.
A sudden and short-lived infectious illness primarily affecting young children. It starts with a rapid rise in fever accompanied by feelings of discomfort. The fever drops sharply and is quickly succeeded by a rash resembling measles, which begins on the back and shoulders, extends to the abdomen, and finally appears on the face and limbs. The rash typically disappears in about two days, and the entire ailment concludes in a few days. Also known as the three-day fever.