Roseola is an infectious virus that many infants under three years old can catch, but is most common in infants under age one.
Roseola is thought to be caused by the human herpes virus six.
The first symptom you will notice in your baby is an unexplained very high fever. The fever can be as high as 104 to 106 degrees, which is very distressing. The fever can last from one to five days and then disappear. Within twenty four hours later a rash will appear on the neck, upper arms and the trunk, and then spread to the face and legs. Your baby may also get diarhea, nausea, and vomitting.