Toddler with itchy eyes, red around eyelids, no discharge

Our 3 yr old daughter has been constantly rubbing her eyes for the past 3 weeks. Her symptoms are itchy eyes, slightly red around eyelids, slightly purple around the eye socket (has been rubbing them alot..), a runny nose, and possible light sensitivity (she has to have her shades when we go outside, which only started recently).  Our pediatrician says that she has allergies and suggested OTC Zyrtec (half dose), and Zaditor eye drops. We followed the doctors orders and the symptoms have persisted.  We've also tried Benadryl, Dimetapp, Mucinex, pretty much every childrens antihistimine and nothing seems to be helping her.  We feel so bad for her, she says they hurt sometimes, and I know the the constant itchyness would drive me crazy!  Please help..  Thank You