Marilyn,
Was your dog tested for hypothyroidism?? Your description of his symptoms - especially the bad smell- sure sounds like it. I had a friend with a dog that smelled so and itched so much they almost had her put down. Then they tried a new vet who tested for hypothyroidism. Sure enuf - it was very low. Put on thyroid med and the dog responded almost immediately - She lived a good like taking her thyroid meds.