Ok. Thanks for the response.
I think this sounds like it might be allergies.
The shampoo you are using probably helps to soothe the skin, but you will likely need a stronger shampoo in order to be effective. Typically, these can not be purchased over the counter. However, there are several your Vet should have in stock to help you there.
Creams can be helpful on local areas of rash - but you might consider one that has hyrdocortisone in it. These may be applied for short periods of time on localized rashes.
Another treatment you can try is antihistamines - Certain antihistamines will work for some pets and not for others. For some benedryl at 1mg per pound helps every 12 hours. Keep in mind that this won't work as well for mites or infections. Another prescription medication is hydroxyzine. It works very well at blocking ITCH not just as an antihistamine.
And actually, what might help the most, and is VERY easy to try is adding in fatty acid/fish oil supplements to the diet. These nourish the skin, and replace normal oils. They are also anti-inflammatory so they help decrease the inflammation that leads to itch. This would, of all the things I have mentioned, likely be the first and easiest to do.
There are MANY types out there. Every petco and petsmart will have similar products. I like this one Click here
In the end, allergies can become very complicated. So, you might need a lot more work up. This can get costly, but you might spend more in the long run trying to figure out the problem and trying different medications on your own.
So, I need to give you this information about alleriges. And it is very long. Please read through it and consider some of the options I am recommending to you as I think they are the best answer I can give to help you and your pet.
Steroid shots are kind of a last ditch option for allergies and skin problems in pets. They work GREAT and do stop the itch right away. So, they can be used for that. But they don't really adress the problem they just mask the problem.
I recommend a skin scraping to look for mites. These are often very deep under the skin and because of that you might not see them with the first scraping. You may have used some flea and tick meds, but these don't always get scabies for example. Revolution is a good product that does.
A pluck of the hair is good idea too to rule out other causes of infection, irritation like fungus. It might not look like ringworm, but until the pluck is done you can't be sure.
Also, a smear of the skin might reveal that there is actually an infection below the surface that you can't see. Yes, this does happen. Some of these pets will need to be on antibiotics for 4 weeks or more to be sure.
Lastly a skin biopsy is not a bad idea with chronic issues. It sounds worse that it is. Usually this is like what your doctor might do in the office. A little local, a punch biopsy tool, and a suture or staple to close and you are going back home again.
Dermatology gets confusing. Because of this you might need a dermatologist to iron it all out. This link will help you find one in your area. I know you may have spent a lot already, but you will spend MUCH MUCH more trying to figure this out than just going to a dermatologist for pets. Trust me: Please click here for dermatologist information - you'll be glad you did
Changing the food is a good idea. But food changes may take up to two months or more to show positive effect. IT's not just the quality of the food but the protein source. Your dog might be allergic to proteins in the food or wheat gluten, etc.
The food I have seen the best results with is Wellness brand. People are loving it! And they keep telling me. I figure that most people don't like to tell you when something is working, they usually will tell you when it doesn't. But this is the opposite of that. My clients really say it helps. I don't get paid by Wellness, but I wish I did. Click here for that link
This link will also help you understand a proper food trial for allergies [http://www.veterinarypartner.com/Content.plx?P=A&S=0&C=0&A=2499](CLICK HERE)[/url]
In the end your pet might have to be tested for skin allergies. This might cost some money, but will be well worth it in the end.
There are medications for atopy, or inhalent allergies, that work GREAT in pets. One is called Atopica. It isn't super cheap, but there are ways to get the price down. Most smaller pets for example can get down to about $30 a month, which is really actually very cheap when you think about it. Here is a link with their information as well. Truly consider at least trying it. The results are often amazing! http://atopica.com
SO there are lots of options. Unfortunately, none that are free. BUT, these suggestions I gave you I give because they often DO work. So, don't be afraid to try them.
Good luck. Please accept my offer to help.