What would you say is the main trigger for your skin issues and what do you believe the underlying cause of seborrheic dermatitis may be?
A very good question! I had acne as a teenager and into my early twenties which is not good re self-confidence and causes feeling of stress over my appearance. I don’t know if the acne was a result of stress through those years or not, but it cleared up when I became pregnant and never came back. What I did notice in later years, was that my scalp was greasy. Not dandruff, just a pasty sort of exudate. Even back then I wondered if I should see a dermatologist about it but never did since it did not bother me in any way, other than I noticed it - could scrape it off with a fingernail. Washing my hair a lot kept it from being a problem also.
Many years later I discovered a couple of scaly patches on the crown of my head which did send me to the doctor who diagnosed it as a pre-cancerous type of scale build-up, and I also had a couple of on the back of my hand. They were treated with liquid nitrogen and went away. A couple of years later, more appeared so I went back to the doctor, but this time she said it was SD. I won’t go into all that has transpired since then in trying to deal with it but no matter what I did, it just kept spreading. It is like the greasiness has turned into hardened scale. I am now 75 years old and have drier skin overall. If stress is a factor, it does not surprise me since I am prone to feeling anxious a fair bit. Also I have been smoking since I was 16 and still do although far less than in the past as I am working on being healthier overall. 
Bottom line, I don’t know, except that I am prone to having it. No other member of my family has had this condition so I don’t believe it is genetic as such. Looking forward to what other members of the group think about it!
As always, thank you Michael!
Sharon