DD had roseola and her rash came and went over a couple of days. the rash is very fine... roseola is very hard to diagnose apparently... It is typically a high fever for 3 to 4 days with irritability and then the rash appears but is often very fine and faint ad short lived. When DD had it, her fevers were 39 to 40 and we actually just thought she was teething until she got the rash. The only reason she went to the Dr with the rash was because she had started Antibiotics two days earlier for an ear infection and I needed to make sure it wasn't a reaction to that... She was totally fine within a couple of days.

HTH

MG