Cat Issue

Hello!

My cat ( neutered black & white shorthair) has taken up the practice of licking the fur on his lower legs. There are more bare skin patches showing every day. He is mainly an outdoor beast, but has been inside most of the winter. At his yearly vaccination/checkup, the vet pronounced him healthy & wasn't concerned about the loss of leg fur. (It had just started then & is getting worse)

Any suggestions to stop this??

Thanks muchly,

Wayne