Jesse's skin issues revisited-suggestions needed

Since it seems to be environmental, have you tried giving him Benadryl during flare ups? Dogs can have 1 mg. per lb. of body weight. Since tablets are 25 milligrams, dose accordingly. You can also get a pill splitter, if he's between whole pill dosing. Make sure you get plain Benadryl tablets; nothing else added. Wally World and stores like Costco, B.J.'s, Sams, etc. have store brands really cheap.