Hi there. I suffer from Seborrheic Dermatitis since 4 years. I am currently on my last year of master's degree of medical chemistry (see the irony:)? Been using a cream with 0.5 % ZnPT as active ingredient (not the one you mentioned) for past 2 years and my SD is 90++ % at bay. What I am lately concern is that ZnPT is effective on SD not only with his anti-fungal but more with it's anti-metabolic effect, with other words it inhibits the cell growth (avoid the new skin pushing the healthy one before it's normal replacement-reason for the flakes- by slowing the process.
Now we need to distinguish usage of ZnPT in shampoos from the creams, simply because the first is rinsed off and the other is left on the skin. So keeping that in mind such a repression of skin DNA could teaoretically cause the DNA to try fight it - faster skin growth, faster and thick hair growing. From what I understand you have been using zinc pyrithione cream for eight years straight or you been using it once in a while? And how is that reflecting to your skin and hair? Your experience is of great interest to me and others I hope.