Thank you for your question. My name is***** I have been a small animal veterinarian for 13 years and I'd like to help with your question.Dogs itch primarily for two reasons.... infection or allergy. And most dogs that are severely itchy as your girl is have both. There is a good chance that this is going to be a lifelong struggle for you and her, but one that you can manage. You will need to work with a veterinarian that can examine Bailey for much of it, but here is the general approach to getting things under control.First, we must deal with any infection present. Most of the time the real problem is allergies, but once the skin is traumatized by itching the infection inevitably come along. You need a veterinarian to take a sample from her skin and look under the microscope to see what infections might be present... generally mites, yeast, or bacteria can be present. Then you need to get an appropriate antimicrobial to treat the infection. This is the easy part..... it might require weeks of treatment, but usually it is successful.The much more difficult part is dealing with the likely allergic component. Switching food was a good start, but most dog's allergies are not food related. The most common allergy is actually flea allergy. Even if you have never seen a flea, every itchy dog should be on good flea control. This means that Bailey and every animal in contact with her should get (advantage/frontline/comfortis/nexgard) once a month or Bravecto every 3 months. Most flea allergic dogs have the most severe itching above their tail and in their arm pits. The food change was good, but often allergic dogs actually need to go to a hypoallergenic
diet. These are often available only through a veterinarian and are expensive. Whether I would try this depends a bit on what they have been eating and where they are most itchy. Food allergy tends to cause ear
and feet itching.It sounds like Bailey is itchy everywhere... this is most commonly atopy
or environmental allergies. These can be very difficult because, short of moving, you can't just change their environment. Usually you need prednisone initially to reduce the itching and inflammation to allow the skin to heal. It is not a good idea to stay on the Prednisone long terms so once things are under control we try other things to control the itching. It is a bit of trial and error. The shampoo and oils do help at this stage. There are also other anti itch medications that can help... such as apoquel. It is about trial and error. And sometimes dogs still need to go back on prednisone in the spring or fall when the pollen counts are highest.I hope that helps but if you have additional questions please let me know. If not, please rate my answer.