I found a site call
www.pawlicking.com that is very informative. It seems like it could be allergies, stress, anxiety or even a psychological tendency. The important thing is to determine what causes an individual dog to lick its paws. It's a matter of elimination to find the problem.
I definitely think she has a problem - sometimes she almost bites them as well. Perhaps on her next vet visit he must look at it more carefully. She makes them red from her licking eventually. I dont like to be hard on her so sometimes I just cover her feet with my hand and she just carries on licking my hand. They say the licking leads to other skin problems too if not corrected.