Dermatitis herpetiformis is a skin manifestation of celiac disease. It causes extremely itchy bumps and blisters that resemble herpes lesions, although it has nothing to do with herpes. Dermatitis herpetiformis can occur on any part of the body, but is most common on the forearms, buttocks and knees. The rash can come and go and it's often mistaken for eczema, because the blisters can be very small. That means a lot of people experience the rash for much of their life and never realize it is caused by celiac disease. This is a problem because celiac disease can cause a lot of silent harm to the body, without causing many symptoms until a serious disease is diagnosed. Dermatitis herpetiformis tends to occur in people with celiac disease who don't experience any digestive discomfort. Many people associate celiac disease with symptoms such as abdominal bloating, gas, diarrhea or abdominal cramps and think you can't possibly have celiac disease if you don't get those kinds of problems. The interesting thing is that celiac disease is increasingly presenting in patients with non-intestinal symptoms, such as fatigue, anemia, headaches, infertility or joint pain. Long term undiagnosed celiac disease can present initially as another autoimmune disorder; most commonly under active thyroid gland (Hashimoto's thyroiditis) or type 1 diabetes (which is becoming increasingly common in adults and sometimes referred to as latent autoimmune diabetes of adults). The take home message is please do not ignore symptoms or health problems you may have, even if you think they are trivial. Symptoms are your body's way of trying to tell you something is wrong. The sooner a health condition is diagnosed, the better chance you have of a full recovery. For more information about gluten and how it could be harming your health, see the book Gluten: Is it making you sick or overweight? Reference