Hard skin rash

1 year old Doberman has a rash type thing under his armpits and rear legs , rash feels hard to touch kind of like leather, super ichy , also have noticed white bumps throughout his coat almost like old scars. Have tried hydrocortisone spray, sulfodene ointment and anti fungal anti bacterial shampoo. Went away for a few days an has now come back

Hello - did you try these remedies yourself or were they prescribed?  There are generally two issues to be solved with any itchy dog.  The first is what is making them itch? The second is any damage they do to themselves by itching (which of course, makes the skin inflamed and makes them itch more, so causing a 'vicious cycle').   The second is usually quite pressing on the first presentation, because patients are uncomfortable and struggling.  Typical treatments at this stage might be topical *eg cream / shampoos and so on).   However, there may still be the problem of what's causing the itching in the first place; common ones include fleas (which arent always on the dog), allergies, mites and pain or discomfort in abdomen or the hips, for example. As the symptoms appear to be recurring, your vet ought help you to consider both issues moving forwards.