My 12 month old is being tested for celiac disease and other allergies. hard to tell which items cause what symptoms?

DH: Dermatitis herpetiformis is an extremely itchy rash made of bumps and blisters. The rash is chronic, which means it continues over a long period of time. Dermatitis herpetiformis usually begins in people age 20 and older, although children may sometimes be affected. It is seen in both men and women. The cause is unknown. However, dermatitis herpetiformis is frequently linked to gluten sensitivity.