Poor guy. These are classic signs of allergic dermatitis: licking/chewing at the feet and redness/irritation of the paws and lower limbs. Sherlock likely has an lallergy to something in the environment or certain ingredients in his food. Often-times it is a process to determine what the underlying cause is, but here is some information on how to get started.
https://veterinarypartner.vin.com/default.aspx?pid=19239&id=4952662https://veterinarypartner.vin.com/default.aspx?pid=19239&id=4952600While determining the cause of your pets allergies, it is best to get him on allergy medication to help control his symptoms (licking of the feet). The two most commonly used treatments for dog allergies are Apoquel or Cytopoint. Ask your vet about them to gain more information and develop a regimen that works best for Sherlock.
In addition, you should look into a medicated shampoo for topical relief. Duoxo calm shampoo is available online and works really well.
I hope that Shelock is able to manage his allergies well soon! Best wishes and take care.