It sounds as though your dog has some type of dermatitis, and if she is itching constantly, I would suggest that is it exzema.
You say that you have moved and prior to this the cordisone shots from her old vet gave some relief. How far is this vet's office from your new home? I ask this becaue if your girl is otherwise healthy you may feel more comfortable driving to see him 2 times a year so that he/she can give her the shots.
The prednisolone that her new vet is giving her is a form of cordisone. The Cephalexin is an antibiotic the they are giving her to prevent secondary infections that could result from the itching. If she doesn't have open sores, she doesn't need the Cephalexin. Though I am no vet I don't recommend giving a daily dose of antibiotics as a precaution, because canines like humans will develop a tolerance to this (even when given in low doses). When your girl needs to be treated with an antibiotic her potential success may be diminished.
I don't know about skin allergies intensifying, but the new area that you live in (grass in your yard) may contain more of the allergen that is causing her problem.
I am going to suggest that you skip the medicated shampoos as these can irritate exzema depending on the detergeent (cleansing agent) that they are formulated with. I am going to suggest that you go to your local department store and purchase Aveeno liquid soap for dry, itchy skin and bath her with this. While this may sound silly, there are only 2 genes that separate dog from man and this is why medications that are used to treat dogs are the same things their human counter parts are treated with.
You may also want to get a tube of Cortisone cream (Hydrocort 1%) and apply this to her skin 3 to 4 times a day. There is a trick to this that the average consumer isn't aware of. When using this type of product, less is = to more. A small amount should be massaged well into the skin versus a big squirt so that it glides on easily.
These suggestions are provided based on the fact that you haven't stated whether or not your girl has any oozing lesions. Not that this would harm her, even in this situation, but I wouldn't want to have the vet DC the antibiotic if this is the case.
These suggestions are primarily for her in the event that her skin is dry and flaky. You can also give her a Vitamin E tablet daily. This is easy to do. If she doesn't like to swallow pills all you have to do is break the capsule into her food. The Vitamin E will help to hydrate the dermis from within. There are dog foods that provide (added) fatty and amino acids that are designed to do this also.
If the drive is to much to take her to the vet there is another solution available. She is your pet and you can have your old vet give you a copy of her records and demand that the new vet use this treatment approach. Afterall, it is your "baby" and you are paying this vet for his services, not vice-versa.
Good Luck to both of you. If I can help you with anything else, please let me know. You may request my assistance when visiting Just Answer if you so desire.
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