We just returned from our trip to Reno and Maggie has broken out in a horrible rash and hives.. She has had only her hypo-allergenic food, no treats, has eaten no bugs.. (..that we know of..) and is broken out around her face, lips, tummy, under her legs and also has some weeping in 2 of her face wrinkles.. Her breathing is mildly labored, but we are watching her very closely.. Please help..

Is benadryl O.K. to give to her..?? Is Benadryl cream on the tummy O.K...?? Should we take her in to the ER vet..??