Celiac disease is considered a disease of the digestive system as well as an autoimmune disease. It causes damage to the small intestine, which interferes with the absorption of nutrients from food and triggers an abnormal immune response to foods containing gluten. The disease affects people worldwide, including more than 2 million people in the United States.
Gluten, which is a protein found in wheat, rye, and barely, may also be present in products such as medicines, vitamins, lip balms, and many processed foods. Because people who have celiac disease cannot tolerate gluten, it’s very important that they learn to carefully read labels and identify foods that may contain gluten.
Gluten triggers an abnormal immune, or autoimmune, response among people with celiac disease. This abnormal activity involves the villi, which are small, fingerlike protrusions that line the small intestine. The villi are supposed to allow nutrients from food to be absorbed into the bloodstream, but in celiac disease, the immune system destroys or damages the villi when gluten is ingested. As a result, it’s impossible for a person with celiac disease who eats gluten-containing foods to be properly nourished, as the digestive system cannot absorb nutrients in food.
Celiac disease runs in families, so those with a genetic risk should be particularly aware of its symptoms. But because the disease may be diagnosed late in life or misdiagnosed, not having an immediate relative who’s been diagnosed doesn’t mean that you’re not at risk—celiac disease may run in your family but may not have been detected yet. Anyone who experiences the following symptoms should consult their healthcare provider about celiac disease.
As you can tell from the list above, the symptoms of celiac disease of varied, as is the age when symptoms appear. The reason for this is not fully understood but may be related to factors including the length of time a person was breastfed, the age at which a person began eating foods containing gluten, the amount of gluten-containing foods consumed, and age at diagnosis (though some people have celiac disease long before it’s diagnosed).
It’s also true that not everyone with celiac disease will develop symptoms. Even without symptoms, however, the disease can still cause serious health complications related to malnutrition. Anyone who has a close family member with celiac disease should consider screening (see more about screening in “How is it diagnosed?”).
Celiac disease also affects children, though symptoms tend to be different from those of adults—namely, children are more likely than adults to have digestive symptoms. Celiac disease is a particular concern among children because they need to properly absorb nutrients from food to ensure healthy growth and development. Children may experience the following symptoms:
Celiac disease can be difficult to diagnose because its symptoms may be confused with other diseases, such as irritable bowel syndrome, chronic fatigue syndrome, and inflammatory bowel disease. Fortunately, however, effective screening tests are increasingly available and doctors are becoming more familiar with symptoms. Here, some of the screening tests currently being used are described.
Because celiac disease involves an autoimmune response, people with the disease have a higher blood level of proteins that react against the body’s own cells or tissues when they eat gluten. Called autoantibodies, these proteins can be measured with a blood test. Because autoantibody levels will be raised by eating gluten, it’s important to continue to eat gluten before the test. Otherwise, test results may not indicate celiac disease even if it is present.
When a blood test indicates celiac disease, the next step is to confirm the diagnosis with an intestinal biopsy. This involves the removal of tiny tissue samples from the small intestine, which the doctor inspects for damage to the villi. An intestinal biopsy is performed using an endoscope, a tube passed through the mouth and stomach and into the small intestine.
Dermatitis herpetiformis (DH) is the “itchy skin rash” listed under symptoms of celiac disease. DH is an intensely itchy irritation that can also cause blisters and usually occurs on the elbows, knees, and buttocks. It affects 15 to 25 percent of people with celiac disease; these people may have no digestive symptoms.
To diagnose DH, a doctor will use a blood test and a skin biopsy. Because celiac with DH is both an intestinal disease and a skin disease, it’s treated with two approaches: 1) a gluten-free diet to manage intestinal symptoms and 2) antibiotics to treat the skin disease (skin symptoms will also improve with a gluten-free diet).