Yes, I think it is a contact allergy and thankfully a mild case (so far). He quit chewing after I rinsed his paws and sprayed them with anti-itch spray. He started again after we went back outside for a play time. I will have to be vigilant about keeping his paws clean after playing outside. The anti-itch spray killed his desire to chew almost immediately. (It also worked on my ankle today after I stepped in a fireant bed!
)
I believe it to be a seasonal allergy which will clear as soon as we have a first freeze (which here can be into December).
We have the misfortune to live in the Fall 2007 Allergy Capital of the US. Austin is usually in the top 10 and always in the top 20...just this season we are the #1 allergy city in the country. One of the news stations did a report just today on local allergies affecting dogs and cats in addition to us humans.
Here's the US report (from the Asthma and Allergy Foundation of America) for anyone interested to know if your US city is an "allergy capital" on the top 100 list.
http://aafa.org/pdfs/FALL%20caps%20PUBLIC%202007.pdf
Also I found an interesting allergy article from a local vet to help distinguish contact and/or air "seasonal" allergies, from food allergies. Also techniques to help manage allergies in dogs.
ITCHING AND SCRATCHING