Hi, I worked in vet hospitals for oh 13 years? Our labrador also had allergies to a certain dirt near our house in QLD as well as Wandering Jew.. its a weed and sometimes an ornamental garden shrub. 90% of dogs are allergic to it.

When an allergy is on the legs/feet, its often an allergy to a grass/dirt/shrub that they walk through often. Oatmeal baths soothe the feet, but won't help long term. A cortisone cream can help as well, but being a labrador they often lick it all off....

Our labrador outgrew the issue when she was 2 years old. I did have to use cortisone when it got bad, and often would give her baths in a solution that has chlorhexadine in it to get rid of everything on her skin, I would set up a shell pool, fill it with a soapy solution with chlorhexidine and feed her one kibble at a time for a few minutes while splashing around her feet....

HTH!