My 13 year old daughter has ran a fever for 11 straight days. This morning we noticed a red rash on her upper body. The rash is only on her torso, not on her arms, legs, face or anything else. She states that the rash does not itch. She has had no other symptoms besides the fever. We went to the doctor 2 days ago, and she came back negative for every test. Any ideas what this could be?