I treated a dog for many years off and on with ivermectin (IVOMEC cattle ivermectin from the feedstore). Has to be given orally, I can't remember the dosage, maybe 1 ml for a 65 lb dog? I always worried about giving this to the dog, but he lived to a ripe old age of 16 so I guess it didn't kill him!
Interesting about the revolution. I thought that when he was on revolution (for heartworm preventative) it helped a lot. But the vet at that time didn't have any information supporting revolution as a treatment. The good thing about the ivermectin is if you give it daily it takes care of heartworms too.
The way the law is written in most states is that you can pretty much treat any animal you own however you want. with whatever medications you want. It's only considered practicing without a license if you are treating an animal not owned by you. That however doesn't apply to OTC meds, since they are not prescription, and it doesn't apply if you are giving meds as directed by a vet, then you can treat anyones animals, as directed.
Personally I would go for oral ivermectin over topical, it's such a small amount it's easy to give on food, and it's much less messy than trying to do topical.
Demodex is definatly made worse by periods of stress or immune supression, however in cases considered generalized and not facal it often will not resolve on it's own, and needs to be treated to prevent long term scarring of the skin and hair folicles. Plus it's a pitty bull, and they tend to be more prone to begin with.
ivermectin, for instance, is designed and packaged for cattle and swine, not for dogs. However, it is widely used by dog owners as a less expensive alternative because it is the same ingredient that is used in other parasite control medications for dogs (like Heartgard for Dogs).
The trick however, is using the correct dosage for your dog and administering it correctly.
So, if you plan on going this route, PLEASE discuss it over with your Veterinarian first. Again, it is a poison and improper usage could have devastating effects. Read more for detail