Hi and WELCOME
!
Allergies in dogs is tough - I feel your pain. Benadryl is an 'okay' med, but it's not great bc you have to give it 3-4x a day bc it doesn't last long. Instead, most Vet Dermatologists recommend either Zyrtec or Claritin bc you only have to dose once a day.
Since she is so symptomatic, you actually may want to try Temaril-P instead - it is a prescription and contains both a steroid (helps w/ inflammation/symptoms) and an antihistamine. If she is fairly miserable, I'd go with this stronger med. If her allergies are nearly year round, then I'd go with Atopica.