I have an itchy dog, too.
First off, have you been or will you be going to a vet dermatologist? I do and it really has been helpful. While most regular vets have extensive knowledge of allergies, they don't always have or know the latest and greatest.
I have used Atopica and then transitioned to regular cyclosporine with Leah. It didn't really help a lot. I think it helped in the sense that I was able to get some of her feet issues under control and her general overall skin health in check. I have since taken Leah off of it. My choice, not my vet derm.
In your post you didn't mention if a thyroid test has been done yet? If not, you need to have the vet run a *complete* thyroid test done. Not just the T-4 that is usually done. This test will tell a lot. If thyroid is low this could be causing some of the skin issues.
You mention pustules, you need to find out if this is a staph infection. I don't know much about staph as Leah never had it. From what I've read you really need to get that under control because it can get out of control. Do some searching on that and see the vet if you haven't already.
Allergies are a real pain in the butt and each case is different. With that said here is what I do for Leah:
Feet: OMG in the beginning I thought she would chew those toes right off. I will tell you this: It took MONTHS before I got this under control. Now she has pretty white boxer feet. At night when I take my make-up off and get ready for bed Leah gets wiped down from head to toe with a clean, soft rag with water every night that isn't her bath night. Clean and dry well between the toes.
Bathing: Leah gets a bath every week with a shampoo called Douxo Chlorhexidine PS. Google Douxo.com and the company website is: Sogevalus.com. At the Sogeval website lists all products made and links to helpful information. Leah is on this particular shampoo due to her yeast issues and has bought of folliculites. Please remember that I didn't choose this product on my own, my vet derm did and let me tell you it has been an absolute live saver for Leah. Also, I clean Leah's ears once a week. You have to keep on the ears once you clear up the infections or they will come back. I noticed if the ear is itchy the feet are next.
Antihistamines: Leah has tried all of them except Allegra. Leah can't take Benadryl anymore because instead of it calming her she becomes very hyper. All the over the counter antihistamines can be tried with the supervision of the vet so that the correct dosage is used and never get those pills with a decongestant in the formula. Dangerous to dogs.
Leah also had skin allergy testing done and is on a weekly shot for that. It only helps a little. Leah happens to on the edge of the 30% of dogs that don’t respond to immunization shots.
You didn’t mention what kind of diet Harley is on? Make sure it is a grain free food. If you haven’t checked it out, see: dogfoodanalysis.com for an extensive list of dog foods and ratings. I have Leah on a limited ingredient diet. Avoid lots of carbohydrates as those convert to sugars and sugars cause yeast problems.
Leah is also on a fish oil supplement daily along with her antihistamine. Research suggests that taken together the two create a more synergistic effect than taking one or the other separately.
I haven’t used this a lot, but apple cider vinegar with the “mother” floating in it also can help a lot. I never gave it to Leah in her water, as many people do, I did use it several times on her feet to help with clearing up the feet as long as there isn’t any open or seeping wounds on the feet. I’ve been reading and hearing of people having really good luck using virgin coconut oil. Do a search on BW for either the apple cidar vinegar or the coconut oil and many posts will surface about the uses of these two items.
You can also search using my user name and look to see if I have more information on another post.
The other piece of advice is: Keep a journal everyday of what the skin was like, what you used and list the pros and cons for the day. It really helped me to track what I did and what I didn’t. When you’re at the start of this long road of allergies you try so many things that you can get lost. Remember, to give each new thing you try time to work. You don’t always see results immediately. I know it’s hard, but you will get some where, it takes time.
Good luck, keep researching and trying things out and come here for advice or to talk it out if you need to!