Allergic skin reactions

I have a horrible rash that has been spreading over my legs for the past several months. It began a small lumps on the inside of my knee which I know have formed when I feel a severe biting sensation. These bumps then will stay for days or weeks and not do much. Then, after they have been around for a while, they will suddenly start itching like crazy and become inflamed- and look like hives. Then the swelling will settle- and they will turn into sore red bumps that take a week or so to go away. This began on my knees, has spread to the back of my thighs and is now working it's way down the front of my leg. It has happened for the last four years on and off- sometimes very severe other times mild or non existent. I don't believe that I was accurately diagnosed by my dermatologist because my condition never left. Could this be a food allergy? I have photos as well from a recent flare up. What could this be? Thank you!