My shitsu had the same problem and we eventually couldn't stand it anymore, as she had been bathed in flea stuff ect...so I finally took her to the vet and she had biting lice...yes biting lice, which you can see other than it kinda looks like really tiny spots on her skin, not her hair....The vet gave us stuff and, we shaved her down, bathed her again, and gave her meds. it didn't take long before they were gone. lots of work, as you have to vacum, wash all the dog's bedding, and if your dog sleeps with you, you have to clean your bedding also....in the mean time, you can give them a 1/4 of benadryl as per the vet....