DH isn't SIMILAR to celiac, it IS celiac. It's just that DH manifests in the skin rather than the gut. Quite a few folks with DH have no gut symptoms, although some do. Usually if they do, those gut symptoms are milder.
The way to know for sure is to see a dermatologist and have a biopsy of CLEAR skin near an ACTIVE lesion. Read as much as you can in the DH section here. There are some very smart and experienced folks there. Squirming Itch and PricklyPear in particular.