Here is an article that discusses the cause of dandruff which is basically seb derm that affects a different area. What I find fascinating is that dandruff (and or seb derm) is caused not so much by an actual fungus (malassazia) but the fatty waste products it produces. Everybody has this fungus but only those with compromised skin barriers are affected by their waste.

Yuck, I know! But at least it explains why so many people with rosacea also have seb derm and why it keeps coming back even after it's killed off. It seems repairing the skin barrier would be a good treatment to follow in addition to topicals that go after the fungus.