Need to know what type and brand would be best

Last year, my dog had several skin issues. We cleared them up at the vet’s with antibiotics and the vet said they were all due to “flea allergies”. Well, my dog is getting hot spots again, on his back. I have checked him up and down for fleas and flea dirt, and he is on a high quality dog food that has not been changed since last fall. He did not itch at all during winter. Does anyone have any advice on controlling itching without the use of steroids?

I have a flea problem in my yard and I do use flea protection for my dog, but they are scratching still and the vet says its a flea allergy, but the injection doesn’t work.

I have 2 dogs a boston terrier and a pug. Both are losing hair and biting their butts. Is this flea allergies or what? Taking them to the vet soon, just need to find out what this is! how do you get rid of it?