I know exactly what you are talking about, I had a Yorkie with those tiny spots on her belly. She had skin problems because of pollen allergies, and I always assumed that it was due to that, but didn't know for sure.
Since yours were infested with fleas, perhaps they had a little flea allergy? Just a guess.
__________________ Life is merrier with a Yorkshire Terrier! Jezebel  & Chuy ... RIP: Barkley  Loosie & Sassy  |