When I first started dating my now wife, my dog Petey (a chihuahua mix) was a splotchy mess. Had been for several years. Our vet had diagnosed him as having a genetic deficiency that didn’t allow him to naturally kill mites that are omnipresent. He had open sores and reeked and the quack said there was no cure. My wife took one look at him and when we were at Whole Foods, she bought grapefruit seed oil and mixed it in a solution. We gave the lil mutant a bath and after he dried, she sprayed it over him and massaged it all over his skin. Cleared right up within the week and we reapply every now and then for safe measure but the former pet shop worker outdiagnosed the dude with a parchment. No thin spots even.