The problem of diagnosis and treatment investigations for us with skin diseases is that research is expensive and in many cases, especially like yours which is uncommon, even if a treatment was found there aren't enough patients to justify the expense of the research.
That's why we need to keep searching on our own and share. I shared results of my use and that of others using cilantro to putting about 40% of GD suffers in remission. One derm said he might mention it to others but the other was completely uninterested in a natural treatment not used in clinical trials. The pharmacutical companies would have no interest in an inexpensive treatment, one which we can pick up in our produce section.