Same like you. Have tried a lot of things. I am certain it has to do with my diet. I tried switching it and change it occasionally but could never nail what affected the it. Lots of people also say it has to do with stress but not to my personal experience. It's not that I don't get stressed, it's just that I've seen it come out bad in calm periods of my life as well. Another factor that I think affects it is weather. I find .y condition to improve greatly when I'm in a dry area like a desert.

I also started taking curcumin pills and I think that it also help.

The problem with seborrheic dermatitis is that its right on the edge between not bad enough to make you want to change your life significantly and annoying enough to make you suffer