1) Stress, I believe stress is the biggest factor, when I'm stressing I can literally feel the seb derm prone areas on my face pulsing.
2) Cereal, I don't think it's a coincidence when I ate cereal (Raisin Bran) specifically on different occasions I get visible seb derm. I only eat oats now.
A 100% working aid
The unrefined deep Sea Salt in hot water is without a doubt something that works. When I had that bit starting to appear near my nose I did this procedure at night before bed, and removed it.