Why does my dog bite his paws?

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Allergies, anxiety, pain, and infections are all reasons dog lick their paws.

Some dogs will do this when their nails are to long, want something to chew on (bone), have anxiety, are bored, oh maybe a rash/flee is on their paw

Well, the above answers seem to cover all the bases except one...sheer boredom. Some dogs left to their own devices too long will begin licking at a paw, and even go so far as to cause injury (commonly known as a "hot spot"). Once they've irritated the paw, they'll keep going back to lick it just as they would any other injury or wound. You can try cleaning it & covering it (a baby's sock with self adhesive tape around it), but if no home remedy works, or it gets really bad, as bleeding or infected, obviously see your vet. They can do a better job covering it, & antibiotics might be needed at that point. We've had a few pretty nasty hot spots (granulomas) over the years, with no real physiological explanation. Btw, another consideration, depending on age, is irritation from arthritis.

Sometimes its behavior, an anxiety based response to triggers for dogs.

I have a dog that has been doing this for months (more licking than biting, but he does nibble). We could not figure out why, because nothing had changed in our daily routine. We started doing some research about this, and it turns out he had a yeast buildup in his stomach due to a high carb low protein food. We knew this because every time he licked his fur turned pink. His saliva was pink due to the yeast buildup. We changed his diet to a higher protein, lower carb diet and he has stopped licking altogether.

There are many reasons why a dog constantly bites or licks at its paws, including anxiety, allergic reaction, dry skin and pain. Biting at the paws is a common occurrence in dogs, but it can cause injury.

To prevent a dog from licking its paws constantly, owners should examine the paw for injury or signs of irritation. For anxiety issues, owners should try to redirect the dog's attention away from the paw. If the biting of the paw continues or causes injury, medical attention from a veterinarian is necessary.