Also called baby measles. A contagious disease caused by a virus. It is most common in babies and young children. Roseola begins with a fever of 102-105ºF and is often accompanied by a loss of appetite, cough, runny nose, diarrhea, and malaise. Almost immediately after the fever disappears a spotty pink rash develops on the trunk and spreads to the arms and neck. This rash fades after about 24 hrs, as opposed to measles has a longer lasting rash and is a much more serious.