jbd3 I haven't heard about your Vitamin D 5,000 theory as a cause of GD and now will pay attention if others mention it. A simple and informative and thorough site about skin conditions, including GD is the New Zealand Dermatology site. They also have the best photos of skin conditions which are helpful when trying to identify a skin disease. They list 5 similarities that those of us with GD have in common. I met 4 of the 5 criteria, the 5th being that most are male. I would be interested to learn if you met any of the listed commonalities.
I also see that you have often been prescribed steroids as a treatment. They didn't help me and often those who do get some initial relief find that once they go off the steroid the GD returns with a vengeance.

@frogger I have been taking 50,000 units of Vitamin D weekly for many years now. I don't think there is a correlation with my Grover's Disease since I was off of them at the time I got the Grover's.