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What causes celiac disease?
Researchers do not know the exact cause of celiac disease. Celiac disease sometimes runs in families. In 50 percent of people who have celiac disease, a family member, when screened, also has the disease.
A person's chances of developing celiac disease increase when his or her genes—traits passed from parent to child—have variants, or changes. In celiac disease, certain gene variants and other factors, such as a person's exposure to things in his or her environment, can lead to celiac disease.
For most people, eating something with gluten is harmless. For others, an exposure to gluten can cause, or trigger, celiac disease to become active. Sometimes surgery, pregnancy, childbirth, a viral infection, or severe emotional stress can also trigger celiac disease symptoms.
How common is celiac disease and who is affected?
As many as one in 141 Americans has celiac disease, although most remain undiagnosed. Celiac disease affects children and adults in all parts of the world and is more common in Caucasians and females.
Celiac disease is also more common among people with certain genetic diseases, including Down syndrome and Turner syndrome––a condition that affects girls' development.
Why are celiac disease signs and symptoms so varied?
Signs and symptoms of celiac disease vary from person to person because of numerous factors, including
- the length of time a person was breastfed as an infant; some studies have shown that the longer an infant was breastfed, the later the symptoms of celiac disease appear
- the age a person started eating gluten
- the amount of gluten a person eats
- age—symptoms can vary between young children and adults
- the degree of damage to the small intestine
Some people with celiac disease have no signs or symptoms; however, they can still develop complications of the disease over time. Long-term complications include
- liver diseases
- intestinal cancer
What other diseases can people with celiac disease have?
People with celiac disease may also have autoimmune diseases, including
- type 1 diabetes
- autoimmune thyroid disease
- autoimmune liver disease
- rheumatoid arthritis
- Addison's disease, a condition in which the immune system damages the glands that produce critical hormones
- Sjögren's syndrome, a condition in which the immune system destroys the glands that produce tears and saliva
How is celiac disease diagnosed?
A health care provider diagnoses celiac disease with
- a medical and family history
- a physical exam
- blood tests
- an intestinal biopsy
- a skin biopsy
Medical and Family History
Taking a medical and family history may help a health care provider diagnose celiac disease. He or she will ask the patient or caregiver to provide a medical and family history, specifically if anyone in the patient's family has a history of celiac disease.
A physical exam may help diagnose celiac disease. During a physical exam, a health care provider usually
- examines the patient's body for malnutrition or a rash
- uses a stethoscope to listen to sounds within the abdomen
- taps on the patient's abdomen checking for bloating and pain
A blood test involves drawing blood at a health care provider's office or a commercial facility and sending the sample to a lab for analysis. A blood test can show the presence of antibodies that are common in celiac disease.
If blood test results are negative and a health care provider still suspects celiac disease, he or she may order additional blood tests, which can affect test results.
Before the blood tests, patients should continue to eat a diet that includes foods with gluten, such as breads and pastas. If a patient stops eating foods with gluten before being tested, the results may be negative for celiac disease even if the disease is present.
If blood tests suggest that a patient has celiac disease, a health care provider will perform a biopsy of the patient's small intestine to confirm the diagnosis. A biopsy is a procedure that involves taking a piece of tissue for examination with a microscope. A health care provider performs the biopsy in an outpatient center or a hospital. He or she will give the patient light sedation and a local anesthetic. Some patients may receive general anesthesia.
During the biopsy, a health care provider removes tiny pieces of tissue from the patient's small intestine using an endoscope—a small, flexible camera with a light. The health care provider carefully feeds the endoscope down the patient's esophagus and into the stomach and small intestine. A small camera mounted on the endoscope transmits a video image to a monitor, allowing close examination of the intestinal lining. The health care provider then takes the samples using tiny tools that he or she passes through the endoscope. A pathologist—a doctor who specializes in examining tissues to diagnose diseases—examines the tissue in a lab. The test can show damage to the villi in the small intestine.
When a health care provider suspects that a patient has dermatitis herpetiformis, he or she will perform a skin biopsy. A skin biopsy is a procedure that involves removing tiny pieces of skin tissue for examination with a microscope. A health care provider performs the biopsy in an outpatient center or a hospital. The patient receives a local anesthetic; however, in some cases, the patient will require general anesthesia.
A pathologist examines the skin tissue in a lab and checks the tissue for antibodies that are common in celiac disease. If the skin tissue tests positive for the antibodies, a health care provider will perform blood tests to confirm celiac disease. If the skin biopsy and blood tests both suggest celiac disease, the patient may not need an intestinal biopsy for diagnosis.
Do health care providers screen for celiac disease?
Health care providers in the United States do not routinely screen patients for celiac disease. However, since celiac disease sometimes runs in families, blood relatives of people with celiac disease should talk with their health care provider about their chances of getting the disease. Some researchers recommend the routine testing of all family members, such as parents and siblings, for celiac disease.1,5 However, routine genetic testing for celiac disease is not usually helpful when diagnosing the disease.
How is celiac disease treated?
Most people with celiac disease have a significant improvement in symptoms when they follow a gluten-free diet. Health care providers typically refer people to a dietitian who specializes in treating people with the disease. The dietitian will teach the person to avoid gluten while following a healthy and nutritious diet. The dietitian will give the person instructions for how to
- read food and product labels and identify ingredients that contain gluten
- make healthy choices about the types of foods to eat
- design everyday meal plans
For most people, following a gluten-free diet will stop symptoms, heal existing intestinal damage, and prevent further damage. Symptoms may improve within days to weeks of starting the diet. The small intestine usually heals in 3 to 6 months in children. Complete healing can take several years in adults. Once the intestine heals, the villi will absorb nutrients from food into the bloodstream normally.
Some people with celiac disease show no improvement after starting a gluten-free diet. The most common reason for poor response to dietary changes is that people are still consuming small amounts of gluten, which can damage the small intestine—even in people without symptoms. Most people start responding to the gluten-free diet once they find and eliminate hidden sources of gluten from their diet. Hidden sources of gluten include additives made with wheat, such as
- modified food starch
Some people who continue to have symptoms even after changing their diet may have other conditions or disorders that are more common in people with celiac disease. These conditions may include
- small intestinal bacterial overgrowth, which happens when too many bacteria grow in the small intestine
- pancreatic exocrine insufficiency, in which the pancreas does not produce enough digestive juice
- microscopic colitis, an inflammation of the colon that a health care provider can see only with a microscope
- lactose intolerance, a condition in which people have symptoms after consuming milk or milk products
- other food intolerances, which may occur because of continued damage to the intestine
In some cases, people continue to have difficulty absorbing nutrients despite following a strict gluten-free diet. People with this condition, known as refractory celiac disease, have severely damaged intestines that cannot heal. Their intestines are not absorbing enough nutrients, so they may need to receive nutrients intravenously. Researchers continue to evaluate medications to treat refractory celiac disease.
Depending on a person's age at diagnosis, some complications of celiac disease will not improve, such as short stature and dental enamel defects.
For people with dermatitis herpetiformis, skin symptoms generally respond to a gluten-free diet and may recur if a person adds gluten back into his or her diet. Medications such as dapsone can control the rash's symptoms. Dapsone does not treat intestinal symptoms or damage, so people with dermatitis herpetiformis should maintain a gluten-free diet, even if they don't have digestive symptoms. Even when a person follows a gluten-free diet, the skin lesions from dermatitis herpetiformis may take months or even years to fully heal and often recur over the years.