Something's biting them

You'll see flea dirt on them if you look deeply thru the coat. 

But fleas will tend to stay on DOGS if the dogs are a good blood source than going to people.  You often won't see them on furniture, if the dog is a good "host". 

But if it's always the 'butt' you may have anal glad problems -- that can cause nerve tingles if they are full.

 My dog is having this problem too, and he gets strange, small bumps on his skin, too.

He does NOT have fleas (as confirmed by our vet), and has also been on Frontline for forever. I have never seen any bugs, and Rascal is white (so they show up easily), and I check him thoroughly (because I'm paranoid). I have never been bitten by anything myself. 

His anal glands are fine (as confirmed by our vet). His bedding gets washed frequently, with verrrrry little soap, and it's the same soap we've always used for him and has never given us any problems.

Our vet just gave up and prescribed him prednisone, but I'm reluctant to use it without figuring out the "mystery itches."

Vet said it's probably "some bug or something." ???

Anyone know of any bugs that can bite, but aren't easily seen?

 bed bugs? that's honestly- the first thing that comes to my mind...

If your home is dry you might also consider it being static electricity. Our cats jump a mile in the air sometimes because they touch the wrong thing or rub against something wrong...because it's dry in here. Always is in winter when we run the heat. Might consider that...try a humidifier.

Cita - there is a Hylands Homeopathic (Whole Foods has it) called "Poison Ivy/Poison Oak" -- it is FOR anything itchy.  Alternatively (and this might be easier to find) there is a homeopathic (Boiron is easy to find -- little tiny blue tubes) called 'Ledum' .

Ledum is FOR stings/bites or anything with a "stinger".  I use the Poison Oak/Poison Ivy myself for the itch of the psoriasis.  (Homeopathics are like that -- usually they will work on more than one thing)

 Homeopathics you want to give without food, without anything else.  They are sweet -- mine think they are treats.  The Poison Ivy/Poison Oak one you can give 2 tablets ... and then give again in an hour if you need to (that's called a "loading dose";)

The ledum -- those are tiny little pellets -- you have to take off the cap and then twist that little collar (holding it down over a small bowl/dish) until you get 3-4 of those little pellets out.  Pour them into a folded piece of paper and then crush the pellets with a small hammer or something heavy and hard.  Then just pour into Rascal's mouth -- it's sweet --mine will lick it up off the floor once they know how yum it is.

My point is this -- if it is something stinging or itchy these will help.  It might actually help you diagnose.

It's not bedbugs or YOU would be itching.  It surely could be static electricity.  But I'd think you'd see the coat crackle.

I would have the anal sacs expressed to be on the safe side.