Looking for help or advise. I have a female DD with a slick coat.who has been losing hair for about 1 yr. The Vet has checked her for mange and other parasites, done skin scrapes ."nothing" changed her food 3 different times, had her on Melatonin for hair loss, Tried not taking her swimming, training in different fields and woodlots, Swimming in different lakes and rivers. Has anyone seen or heard of this problem before in a DD? Any info would be appreciated.