I had a similar experience with my battle with Seborrheic Dermatitis . Eight years of awful symptoms from the disease and just as bad with the medicines. I finally found a message board that said that they were allergic to margarine and the main ingredient Canola oil. So I decided to stop using margarine. It took about 4 months and slowly all of my skin problems started to clear. I have been very clear of skin problems now for almost a year. I have had only one minor flair up when I ate some baking made with margarine over Christmas. It's worth a try if you have run out of options. Hopefully it can help someone else. Good Luck
Just a note: I didn't mention that I switched to butter. I believe that this skin problem relates to what type of oil is in our skin.