My 3 year old has had cold symptoms and conjunctivitis now for 5 days. Last night she developed an itchy rash that came about suddenly with blotchy raised bumps on her torso and extremities. I gave her Benadryl and the rash went away. The rash came back tonight. She has had post viral rashes in the past, but they have not presented this way in the past. I find it odd that the rash only comes about at night and is itchy. Could this still be a viral rash? Thanks!