I've done a ton of research on this horrible condition and I'm sure it's related to the liver and large intestine. I'm taking vsl#3 probiotic sachets but I've only just started taking them so I think I'll have to wait a while until they work. I think SD is related to bad gut flora and some even suggest it's linked to leaky gut syndrome. I don't believe that anythings incurable, it's just the pharmaceutical industry wants to keep us sick and dependent so they can make money from us!
You probably have already, but just incase... be sure to stay away from Sugar dairy and gluten, that definitely irritates it and the fungus breeds on them!
I would try finding some probiotics like the one I mentioned to restore the gut and also try a few liver colon kidney flushes and parasite flushes!!! I haven't yet but I'm sure they will help, maybe even cure it. I think it will take several flushes though. If you have a really bad flare up of SD and need to get rid of it quickly for whatever reason, Water Fasts are sooo good!! It heals within about 4-5 days!
The SD is without doubt the result of somethig else, lots of people use all sorts of things on their faces/scalps to get rid of it, but its definitely an internal as opposed to external, problem.
If the vsl#3 works great, I'll let you know and also if I come across anything else!