Understanding Celiac Disease

by National Institute of Health

What is celiac disease?

Celiac disease is a digestive disease that damages the small intestine and interferes with absorption of nutrients from food. People who have celiac disease cannot tolerate a protein called gluten, found in wheat, rye, and barley. Gluten is found mainly in foods, but is also found in products we use every day, such as stamp and envelope adhesive, medicines, and vitamins.

When people with celiac disease eat foods or use products containing gluten, their immune system responds by damaging the small intestine. The tiny, fingerlike protrusions lining the small intestine are damaged or destroyed. Called villi, they normally allow nutrients from food to be absorbed into the bloodstream. Without healthy villi, a person becomes malnourished, regardless of the quantity of food eaten.

Because the body's own immune system causes the damage, celiac disease is considered an autoimmune disorder. However, it is also classified as a disease of malabsorption because nutrients are not absorbed. Celiac disease is also known as celiac sprue, nontropical sprue, and gluten-sensitive enteropathy.

Celiac disease is a genetic disease, meaning it runs in families. Sometimes the disease is triggered-or becomes active for the first time-after surgery, pregnancy, childbirth, viral infection, or severe emotional stress.

What are the symptoms of celiac disease?

Celiac disease affects people differently. Symptoms may occur in the digestive system, or in other parts of the body. For example, one person might have diarrhea and abdominal pain, while another person may be irritable or depressed. In fact, irritability is one of the most common symptoms in children.

Symptoms of celiac disease may include one or more of the following:

• gas
• recurring abdominal bloating and pain
• chronic diarrhea
• pale, foul-smelling, or fatty stool
• weight loss / weight gain
• fatigue
• unexplained anemia (a low count of red blood cells causing fatigue)
• bone or joint pain
• osteoporosis, osteopenia
• behavioral changes
• tingling numbness in the legs (from nerve damage)
• muscle cramps
• seizures
• missed menstrual periods (often because of excessive weight loss)
• infertility, recurrent miscarriage
• delayed growth
• failure to thrive in infants
• pale sores inside the mouth, called aphthous ulcers
• tooth discoloration or loss of enamel
• itchy skin rash called dermatitis herpetiformis

A person with celiac disease may have no symptoms. People without symptoms are still at risk for the complications of celiac disease, including malnutrition. The longer a person goes undiagnosed and untreated, the greater the chance of developing malnutrition and other complications. Anemia, delayed growth, and weight loss are signs of malnutrition: The body is just not getting enough nutrients. Malnutrition is a serious problem for children because they need adequate nutrition to develop properly.

Why are celiac symptoms so varied?

Researchers are studying the reasons celiac disease affects people differently. Some people develop symptoms as children, others as adults. Some people with celiac disease may not have symptoms, while others may not know their symptoms are from celiac disease. The undamaged part of their small intestine may not be able to absorb enough nutrients to prevent symptoms.

The length of time a person is breastfed, the age a person started eating gluten-containing foods, and the amount of gluten containing foods one eats are three factors thought to play a role in when and how celiac appears. Some studies have shown, for example, that the longer a person was breastfed, the later the symptoms of celiac disease appear and the more uncommon the symptoms.

How is celiac disease diagnosed?

Recognizing celiac disease can be difficult because some of its symptoms are similar to those of other diseases. In fact, sometimes celiac disease is confused with irritable bowel syndrome, iron-deficiency anemia caused by menstrual blood loss, Crohn's disease, diverticulitis, intestinal infections, and chronic fatigue syndrome. As a result, celiac disease is commonly under diagnosed or misdiagnosed.

Recently, researchers discovered that people with celiac disease have higher than normal levels of certain autoantibodies in their blood. Antibodies are protective proteins produced by the immune system in response to substances that the body perceives to be threatening. Autoantibodies are proteins that react against the body's own molecules or tissues. To diagnose celiac disease, physicians will usually test blood to measure levels of Immunoglobulin A (IgA), anti-tissue transglutaminase (tTGA), IgA anti-endomysium antibodies (AEA).

Before being tested, one should continue to eat a regular diet that includes foods with gluten, such as breads and pastas. If a person stops eating foods with gluten before being tested, the results may be negative for celiac disease even if celiac disease is actually present.

If the tests and symptoms suggest celiac disease, the doctor will perform a small bowel biopsy. During the biopsy, the doctor removes a tiny piece of tissue from the small intestine to check for damage to the villi. To obtain the tissue sample, the doctor eases a long, thin tube called an endoscope through the mouth and stomach into the small intestine. Using instruments passed through the endoscope, the doctor then takes the sample.

About the Author

NIH is the nation's medical research agency - making important medical discoveries that improve health and save lives. The National Institutes of Health (NIH), a part of the U.S. Department of Health and Human Services, is the primary Federal agency for conducting and supporting medical research.