Have you tried a heavy metal detox using cilantro. Blend 1/2 bunch of cilantro with water or other smoothie ingredients. Drink daily for about 2 months. I learned about this on the Mayo skin site from GD suffers. It puts it into remission for about 40% of us. I noticed some improvement in 3 weeks, definitely in remission after 2 months and kept it up for 6 months out of fear it would return. I've been clear now for years. Previously my pattern was this, first outbreak at age 65 for one full year, covering all of front and back torso, then 6 months of remission, followed by 6 months of rashes on torso only to repeat. Mine was not only itchy but painful. That pattern held for about 4-5 years until I tried cilantro. Also Google the connection between heavy metals and Alzheimer's, Parkinson's and Grover's Disease. Blood can be chelated by doctors to remove heavy metals, but there are many internet sites with suggestions on how to do this yourself. Besides cilantro, oregano and other herbs work.
On the Mayo discussion a group of us tried it and as mentioned about 40% went into remission. It did take about 3 years for my skin not to be sensitive and return 100% to feeling normal. Perhaps it takes that long to heal internally from the damage.