I have DH, confirmed by biopsy, which cost over $1200 in the US. If you can find a doctor willing to give you a test script of Dapsone, taking it for a few days could be another way of determining DH status. I took just a day for me to notice a significant change in my rash. Hope this helps.
I have DH ( confirmed by biopsy test) and went on Dapsone, and had my rash get much better in days. Since the test was $1300, maybe you could just get a script and see if it works. My doc wouldn't do that. Best. Ps been gluten-free for 4yrs and still have the rash.