SD is related to an impaired immune system. We know this because many people with AIDS have this skin problem. Now how this fits in with those of us without AIDS is the big question. In your case its easy as you are on immunosuppressive drugs. Most people have been on Antibiotics but very few get SD. Bowel flora: interesting theory but yet to be proven. And yes, faecal transplant is the ultimate answer, although it's quite a yuckky idea! Unlike most SD sufferers my problem is not on my face but on the inside of my thighs, arms. A patchy rash that is now so chronic that the skin is atrophic. Tried everything when it started as a young adult, nothing worked. More recently I cut out all carbs for almost a year which did wonders to my waistline but nothing for my SD. In the end I think the solution will be immune therapy. An expensive injection will become available, one day.