Celiac Disease
Extremely itchy bumps or blisters on knees, elbows, buttocks, and/or hairline are signs of dermatitis herpetiformis (DH), a skin manifestation of celiac disease. “When a person with celiac disease consumes gluten, the mucosal immune system in the intestine responds by producing a type of antibody called immunoglobulin A (IgA),” John Zone, MD, Celiac Disease Foundation medical advisory board member told celiac.org.