chewing on feet

Question
I have a 7 year old female Brittany Spaniel. I've noticed her chewing on her back feet and front feet/wrists in the past. She recently started doing it again. I'm assuming her feet are bothering her, I feel like she's in pain maybe its arthritis? She runs around and stuff like usual, she's very happy and playful but she is getting old. Maybe it's allergies so her feet itch? Her vet gave me cortisoothe shampoo a few years ago for allergy in her skin but it's expired now. Is that something I should purchase again? I want her to be as healthy and happy as possible so if she's in pain I want to help her. I will be taking her to the vet sometime in May.

Answer
Hi,
Could be allergies or
Could be baby fleas so tiny you can't see them.  What are you using for fleas.  The best stuff is Advantage, Comfortis, Trifector and Frontline.  Advantix is not as good for fleas as Advantage.
Could be a yeast infection she gets when the weather gets damp.
The cortisoothe shampoo sounds like a great start if you are already using one of the above flea controls.
Know that if she continues to chew it could turn bacterial, so please do take care of it as soon as you are able to do so.
nancy