Hello, I can understand your concenr for celiac disease as well as the skin issues of blisters at left hip and groin area. In my clinical experience it appears to be related a skin condition known as Dermatitis herpetiformis . It is a skin condition which is mainly distributed along the extensor surface of back, buttocks groin and other areas. It is quite itchy condition and is mainly related to celiac disease or in persons who are sensitive to gluten. The mainstay of treatment for Dermatitis herpetiformis is by dapsone. I suggest you to meet a dermatologist and get a skin biopsy done for the same. If it is Dermatitis herpetiformis then you may require complete abstinence from gluten diet. All the best.