Treatments:

Since Roseola is a mild disease, it will go away on it's own.

Ibuprofen is recommended to keep high fevers down.

It is best treated by managing symptoms and keeping the infected person well rested and hydrated.

http://chealth.canoe.com/condition_info_details.asp?channel_id=0&relation_id=0&disease_id=353&page_no=2#Treatment