Your doctor will need to do a skin biopsy. After numbing the area, he’ll use a very small instrument that works like a cookie-cutter to “punch” out part of your skin. You may need a stitch or two to close up the site. It should heal quickly, with very little scarring.
A lab will use dye to see if you have IgA in a certain type of pattern. This tells your doctor whether you have DH. He can then also take some of your blood to test it for celiac disease.