Hello, I am Dr RB and I am licensed veterinarian. As you may know, skin allergies in dogs can be divided into three main categories; flea allergy, food allergy, and atopy/inhalant allergy. Once all of these sources of allergy are ruled out then immune mediated skin disease may be possible. As a result of the itchy skin, the skin barrier often breaks down and become more moist (especially with licking) and secondary skin infection (either bacterial or fungal) occur which just exacerbates the process.
Because you describe sores, I am almost certain that infection is at play here. Flea allergy can be tricky to completely rule out because dogs that truly allergic to flea will have a reaction to the saliva in the flea; so only one flea bite can set things off. That is why monthly flea prevention all year round is important.
Food allergy can only be ruled out via an 8-12 week food trial with a prescription hypoallergenic food (or one containing hydrolyzed protein) with no treats, outside food etc.
Atopy or inhalant allergy involves environmental irritants (such as grass, molds, anything in nature, contact allergy etc). Diagnosis can be via blood serum testing or skin test and allergy injections can be created specifically for your pet.
Here is my advice to you.. Because skin infection is most likely present, due to painful feet with sores, Indie will need to see her veterinarian so the proper medication can be prescribed to treat any infection present. Based on the vet's exam, the correct anti-allergy medication will also be added to this. Most of the time, when feet are involved, inhalant allergy is always at the top of my diagnostic list. The medication you need to ask your veterinarian about is called Apoquel.. He/she will most likely recommend a couple of recheck appointment until the sores have healed. If you have a good relationship with your veterinarian, you may be able to call him/her and ask for a light sedative to give her to help get her in the car:)
I hope this advice is helpful to you. Please do not forget to rate my answer which I hope you found to be excellent! If you have further questions about this, please do not hesitate to let me know:)