My sure fire cure for hot spots is to shave the area to get the
skin to dry out. It works like magic in 2 or 3 days. And while we're
shaving : I do it all the time with never a problem in regrowth.
Last spring I recommended shaving to a friend with a collie who has
one of those dense modern coats. She said it made the summer for man and
dog. I saw the dog recently and she has a perfectly normal new coat.