In a word, yes - if you have a diagnosis for dermatitis herpetiformis and your celiac antibody blood tests also came back positive, you have celiac disease. If, however, your blood tests for celiac disease came back negative, your dermatologist may refer you to a gastroenterologist for an intestinal biopsy, considered the gold standard for celiac disease diagnosis. About 90% of dermatitis herpetiformis patients have a positive intestinal biopsy.
In celiac disease, your body mistakenly attacks the villi in your small intestines. Dermatitis herpetiformis represents another autoimmune reaction from gluten - instead of attacking your intestinal villi, your body's immune system mistakenly attacks your skin. This attack produces an intensely itchy rash with water blisters and itchy red bumps which occurs most frequently on the elbows, knees, buttocks, lower back and the back of the head.
Dermatitis herpetiformis affects between 15 and 25 percent of people with celiac disease, mainly adults, and many of people these have no gastrointestinal symptoms. Although the medication dapsone can help to clear up your rash, you'll need to stay on the gluten free diet long-term to prevent celiac disease complications.
Dermatitis Herpetiformis: Skin Manifestation of Celiac Disease. National Digestive Diseases Information Clearinghouse. Accessed: Sept. 5, 2010. http://digestive.niddk.nih.gov/ddiseases/pubs/dh/