3 year old has itchy bumpy rash on and around both ears. no fever or other symptoms...what could it be??

Dermatitis: skin inflammation due to multiple factures. Impossible to diagnose without a photo. I suggest a pediatric exam.

Allergic rash: Itchy rash is usually some type of allergic reaction. Perhaps a new shampoo, new detergent on sheets, new food? Other possibility is she touched poison ivy and scratched her ears. Anyway give her loratadine or certrizine once a day for 3 days. It should give her relief while you figure it out.