Exanthema subitum (meaning sudden rash), also referred to as roseola infantum (or rose rash of infants), sixth disease (as the sixth rash-causing childhood disease) and (confusingly) baby measles, or three-day fever, is a disease of children, generally under two years old,[1] although it has been known to occur in eighteen year olds, whose manifestations are usually limited to a transient rash (“exanthem”) that occurs following a fever of about three day’s duration.