I don't know, other than a glutening. Many have reported a dh type rash after going gluten-free, then doing a challenge or getting glutened.
I'd look for sources of cc, or think back to your last glutening....
If you think it's dh, you may try a low iodine diet to see if it helps it go away. Most dh is iodine sensitive - and it sure contributes to mine worsening if it flares up. Try the thyca.org cookbook (online/free) for how to go low iodine.
There are other gluten related rashes, and other skin diseases are common in the autoimmune challenged.
I really don't think it was a glutening incident. I almost always make my own food and when I don't I'm very careful about what I eat. I'm still not entirely sure if it's a dh rash or not. I may go to the derm if it doesn't go away. I'll look into the low iodine diet. Thanks.