It might be worth keeping a little diary for a couple of weeks whenever you see her licking. Note what she was doing for the few minutes beforehand, what was going on around her and what you did to stop / distract her. It might also be worth noting other things like what house cleaning products you used that day and whether she had recently been for a walk (thinking long grass etc).

Be careful not to do anything terribly 'active' to distract her in case this has become an attention-seeking behaviour.

Licking his back legs is a new phenomenon which Flynn has developed...His hocks are virtually bald. He's always had very bad skin and his normal habit is to scratch almost constantly, sometimes it's worse than others and at the moment he's got various small bald patches and scabs.

I took him to the vet who ruled out diet (Flynn has been on most kibble under the sun and now he's raw fed so I dont think it's food) and he has no fleas or mange so attributed his condition to Atopy. I personally believe he's affected by grass. I know myself if I walk the dogs over the fields in shorts, I get rashes all over my legs from the long grass and as Flynn has a near bare underside anyway, I think he suffers the same.

The thing I do to try and manage the licking as well as the scratching is simple distraction as I think it's mostly become a habit rather than a necessity now.