I have one with a perpetual Pink Triangle. She licks the area over her spay scar bare. Actually the past year or so, while the fur is very short, it is almost never bare. I have animax for when she licks so much she develops sores, but haven't had to use it in a couple years. She just keeps the fur very very short there, and the pink skin usually shows through.
She licks other things too. Walls, and underneath the table when she is on a kitchen chair.
Here's what it normally looks like, this was taken in September 2010:
here's her reaction to me trying to take a picture of her Pink Triangle