Dusty started that overgrooming when she was about 12-13 her entire belly. No mites, bladder problems etc. We tried collars, bitter apple, feliway, even diet trials in case of food allergies, nothing worked. She would get a rather 'high' look if you'd interrupt her grooming. We came to the conclusion it was a combination of stress (from the other cats picking on her) and boredom because she couldn't play like she used to. She had that problem right up until we had her PTS in July.

My mom has a single cat 9 yrs old that's just now starting to do that, although her spot is very tiny and can be distracted from it so far. We haven't found anything that actually stops it totally though.

Good luck, and love your kitty bald belly and all. lol