FUNGUS ON MY DOG. PLEASE HELP?

My dog had a skin irritation for a year now. The vet has said it's allergies, Fleas and etc. four months ago he finally said it's A fungus (Ringworm) he gave me a special shampoo and it didn't work. In fact it seemed to have irritated him more. I took my dog to the vet again today to get a skin scrape the vet said nothing showed up in the skin scrape but he could have demodex on top of the ringworm. But nothing showed up. So he gave me a oral medicine just in case. (he looked at his skin with a black light.and said he is glowing and has white scabs all over him. He said it's definitely a fungus. he gave me more shampoo and said to scrub him until he bleeds twice a week. Here's my question.. I have two other dogs and neither of them have gotten this fungus my husband and I haven't gotten this Either.. is this strange? Can anyone help me.. he also has a very strong odor on him is this normal with a fungus? Any suggestions will be appreciated