Ok, there is lots to try then.
In dogs the allergens get on the skin and go through the skin to cause an allergic reaction.
Usually they come in contact with something outside that they are allergic to. Then they come inside and have an allergic reaction.
So when she comes inside wash her feet off with a wet wash cloth or sensitive skin baby wipes. Hopefully that will remove the allergens and reduce allergic reactions.
You can give her human Benadryl. 1 mg of Bendryl, per each pound of dog, every 12 hours.
You can apply over the counter hydrocortisone cream, or spray, to her feet 3-4 times a day. It is not toxic if ingested.
You can soak her feet in warm water and epsolm salts twice a day.
Your vet can do an allergy test to see what she is allergic to. Then she could receive allergy shots which are 50-75% effective.
Does that help? Do you have any additional questions?