Try an Honest Kitchen limited ingredient,either Spruce ( duck and sweet potato ) or Hope (beef and chickpea). Maybe turkey , chicken, and fish don't agree with her.
Also try her on a probiotic, best would be a doggie probiotic like Herbsmith Microflora Plus or Proviable DC. Next best would be green tripe, sauerkraut from refrigerator section of health food store, or kefir. Least best but most widely available would be a fat free, plain probiotic greek yoghurt.
For a while till her paws get better try soaking them in water made tea coloured with betadine for 5 minutes daily.