My name is***** and I am sorry to hear that Lulu has skin problems. Your regular vet is on the right track in recommending Benadryl but it sounds like she may have even more allergies now in Florida. These are common in dogs and can be very frustrating.
When I see an itchy dog, I usually think of the following things:
1) Environmental allergies. Treatments can include prednisone or antihistamines, but can also involve the following- frequent (3x weekly bathing to physically wash off the allergens), fish oil supplements, antioxidant supplements and topical cortisone sprays on the affected areas. You can use prednisone long term if you use a low enough dose, I would aim for about 0.5mg/pound of dog maximum per day. You can also consider allergy testing and allergy shots. These treatments are available through your regular veterinarian or you can consider taking her to a dermatologist.
2) Food allergies. These are also common. I would recommend a food trial with a hydrolyzed protein diet (Science Diet, Royal Canin and Purina all have varieties of these formulas.) These diets also have a variety of other ingredients that can also help the skin and reduce the severity of environmental allergies.
3) Fleas- I would be sure that you have good flea control on board such as Nexguard or Comfortis year round in Florida as it never freezes there and the fleas will live year round.
For tonight, I would give Benadryl at about 1mg per pound to help her be more comfortable, but you may need to see your regular veterinarian in the morning.
Best regards, ***** ***** this answer helps you.
Kansas State University,
College of Veterinary Medicine Class of 2001