Update March 2
I'm still symptom-free by using this olive oil / Sea Salt treatment. I'm not cured though, at least not yet - I forgot to use it the other evening, the next day there were some signs of the SD showing up again deep in the folds beside the nose. It could be pushed back by resuming the treatment.
I know this is considered bad practice, answering your own posts like this. However, I think it is important to give some more information about what I've been able to figure out so far concerning my SD and its history. Maybe someone will be able to understand why the olive oil - Sea Salt treatment may work in some cases.
It was only very recently I was able to discover a possible cause of the SD by analyzing my logbooks and other records. The key to the possible explanation goes through the particular yeast that is believed to be linked to SD, Malazzesia furfur/Pityrosporum ovale, and the different ways skin reactions to this yeast may manifest themselves.
During my life I have had two outbreaks of a generalized rash all over my body, affecting the trunk and back, legs and arms, literally everywhere.
First time it happened the physician was unsure what it was, this was 16 years ago (I'm now 44). I got some fungicides to deal with it, but they seemed not to work very well. The rash peaked after a couple of weeks despite the medication, then gradually subsided and disappeared in about two months.
Second time it happened it was just like the first outbreak. This was 2 1/2 years ago. This time I got a diagnosis, Pityrosporum rosacea and/or possibly the folliculitis version. I was told there is no cure but the condition usually goes away by itself after six weeks. It did.
Cross-referencing these rash outbreaks with my dental records, something potentially interesting was revealed.
The records show that a couple of months before the first rash episode, I got a large Amalgam filling. I was a student with poor economy at the time and didn't think much of this inexpensive solution since I already had eight "silver fillings" since before. The existing Amalgam fillings were all inserted when I was a child as a precautionary measure, the dentist thought I had rather deep ridges in my brand new permanent teeth and there would be caries later on otherwise. The old fillings are rather small and of type copper-amalgam, the new large one I got at the time was "ordinary amalgam".
As I said, the first rash disappeared after a few months, and a decade later I got this SD making it so difficult to see the possible link to a cause.
Now consider this: my second general rash outbreak showed out to have happened just a few months after I had this large Amalgam filling removed. It was cracked and leaking, and was replaced with a composite ceramic of some kind. No preventive measures was undertaken, the old amalgam was simply just drilled out. I was ok with the procedure since I had no reason to believe I had any mercury-related problems at the time.
No other tooth jobs worth mentioning have been performed in the meantime, nor before this long period or after. I've been lucky in that respect.
Knowing this potential link to "mercury allergy" (or slow poisoning), I think what I do now is just like a band-aid solution to SD although more effective that the fungicide/cortisone medications I used before. Some day when I accumulate enough guts I will have those old copper amalgam fillings removed as well, this time with all thinkable precautions undertaken by a mercury-knowledgeable dentist.
What is so extraordinary difficult with mercury is the fact that it may take some time between actions that alter the balance, and the effects. Of course it could also be pure coincidences but the cause-effect is too plausible and consistent with what is known about the effects of slow mercury poisoning. I have some other symptoms as well, had them all my life although in a mild forms that are possible to learn to live with.
I'm too scared to do anything about it right now after realizing the possible links to the previous periods of severe rash. Who knows what the effects could be the next time I mess with amalgam. I also think like this: what remains of the mercury in those eight fillings after almost 40 years could be relatively safely deposited after all - at least as compared to releasing parts of it to be deposited elsewhere in my body like in my CNS for instance. Maybe that is just faulty reasoning.
So there you have it, a slice through the history of my SD. Maybe someone finds it inspiring as an approach to attempt understanding what could possibly be behind this dreadful ailment. In my opinion, it seems like a good place to start the investigation by looking at medical- and dental records side by side.