Celiac disease, sometimes called celiac sprue or gluten-sensitive enteropathy, is an immune reaction to eating gluten, a protein found in wheat, barley and rye.

If you have celiac disease, eating gluten triggers an immune response in your small intestine. Over time, this reaction damages your small intestine's lining and prevents it from absorbing some nutrients (malabsorption). The intestinal damage often causes diarrhea, fatigue, weight loss, bloating and anemia, and can lead to serious complications.

In children, malabsorption can affect growth and development, besides causing the symptoms seen in adults.

There's no cure for celiac disease — but for most people, following a strict gluten-free diet can help manage symptoms and promote intestinal healing.

The signs and symptoms of celiac disease can vary greatly and differ in children and adults. Digestive signs and symptoms for adults include:

• Diarrhea
• Fatigue
• Weight loss
• Bloating and gas
• Abdominal pain
• Nausea and vomiting
• Constipation

However, more than half the adults with celiac disease have signs and symptoms unrelated to the digestive system, including:

• Anemia, usually from iron deficiency
• Loss of bone density (osteoporosis) or softening of bone (osteomalacia)
• Itchy, blistery skin rash (dermatitis herpetiformis)
• Mouth ulcers
• Headaches and fatigue
• Nervous system injury, including numbness and tingling in the feet and hands, possible problems with balance, and cognitive impairment
• Joint pain
• Reduced functioning of the spleen (hyposplenism)

Children

Children with celiac disease are more likely than adults to have digestive problems, including:

• Nausea and vomiting
• Chronic diarrhea
• Swollen belly
• Constipation
• Gas
• Pale, foul-smelling stools

The inability to absorb nutrients might result in:

• Failure to thrive for infants
• Damage to tooth enamel
• Weight loss
• Anemia
• Irritability
• Short stature
• Delayed puberty
• Neurological symptoms, including attention-deficit/hyperactivity disorder (ADHD), learning disabilities, headaches, lack of muscle coordination and seizures

Dermatitis herpetiformis

Gluten intolerance can cause this itchy, blistering skin disease. The rash usually occurs on the elbows, knees, torso, scalp and buttocks. This condition is often associated with changes to the lining of the small intestine identical to those of celiac disease, but the skin condition might not cause digestive symptoms.

Doctors treat dermatitis herpetiformis with a gluten-free diet or medication, or both, to control the rash.

When to see a doctor

Consult your doctor if you have diarrhea or digestive discomfort that lasts for more than two weeks. Consult your child's doctor if your child is pale, irritable or failing to grow or has a potbelly and foul-smelling, bulky stools.

Be sure to consult your doctor before trying a gluten-free diet. If you stop or even reduce the amount of gluten you eat before you're tested for celiac disease, you can change the test results.

Celiac disease tends to run in families. If someone in your family has the condition, ask your doctor if you should be tested. Also ask your doctor about testing if you or someone in your family has a risk factor for celiac disease, such as type 1 diabetes.

Your genes combined with eating foods with gluten and other factors can contribute to celiac disease, but the precise cause isn't known. Infant-feeding practices, gastrointestinal infections and gut bacteria might contribute, as well. Sometimes celiac disease becomes active after surgery, pregnancy, childbirth, viral infection or severe emotional stress.

When the body's immune system overreacts to gluten in food, the reaction damages the tiny, hairlike projections (villi) that line the small intestine. Villi absorb vitamins, minerals and other nutrients from the food you eat. If your villi are damaged, you can't get enough nutrients, no matter how much you eat.

Celiac disease tends to be more common in people who have:

• A family member with celiac disease or dermatitis herpetiformis
• Type 1 diabetes
• Down syndrome or Turner syndrome
• Autoimmune thyroid disease
• Microscopic colitis (lymphocytic or collagenous colitis)
• Addison's disease

Untreated, celiac disease can cause:

• Malnutrition. This occurs if your small intestine can't absorb enough nutrients. Malnutrition can lead to anemia and weight loss. In children, malnutrition can cause slow growth and short stature.
• Bone weakening. Malabsorption of calcium and vitamin D can lead to a softening of the bone (osteomalacia or rickets) in children and a loss of bone density (osteopenia or osteoporosis) in adults.
• Infertility and miscarriage. Malabsorption of calcium and vitamin D can contribute to reproductive issues.
• Lactose intolerance. Damage to your small intestine might cause you abdominal pain and diarrhea after eating or drinking dairy products that contain lactose. Once your intestine has healed, you might be able to tolerate dairy products again.
• Cancer. People with celiac disease who don't maintain a gluten-free diet have a greater risk of developing several forms of cancer, including intestinal lymphoma and small bowel cancer.
• Nervous system problems. Some people with celiac disease can develop problems such as seizures or a disease of the nerves to the hands and feet (peripheral neuropathy).

Nonresponsive celiac disease

Some people with celiac disease don't respond to what they consider to be a gluten-free diet. Nonresponsive celiac disease is often due to contamination of the diet with gluten. Working with a dietitian can help you learn how to avoid all gluten.

People with nonresponsive celiac disease might have:

• Bacteria in the small intestine (bacterial overgrowth)
• Microscopic colitis
• Poor pancreas function (pancreatic insufficiency)
• Irritable bowel syndrome
• Difficulty digesting sugar found in dairy products (lactose), table sugar (sucrose), or a type of sugar found in honey and fruits (fructose)
• Refractory celiac disease

Refractory celiac disease

In rare instances, the intestinal injury of celiac disease doesn't respond to a strict gluten-free diet. This is known as refractory celiac disease. If you still have signs and symptoms after following a gluten-free diet for six months to one year, you might need further testing to look for other explanations for your symptoms.

Many people with celiac disease don't know they have it. Two blood tests can help diagnose it:

• Serology testing looks for antibodies in your blood. Elevated levels of certain antibody proteins indicate an immune reaction to gluten.
• Genetic testing for human leukocyte antigens (HLA-DQ2 and HLA-DQ8) can be used to rule out celiac disease.

It's important to be tested for celiac disease before trying a gluten-free diet. Eliminating gluten from your diet might make the results of blood tests appear normal.

If the results of these tests indicate celiac disease, your doctor will likely order one of the following tests:

• Endoscopy. This test uses a long tube with a tiny camera that's put into your mouth and passed down your throat (upper endoscopy). The camera enables your doctor to view your small intestine and take a small tissue sample (biopsy) to analyze for damage to the villi.
• Capsule endoscopy. This test uses a tiny wireless camera to take pictures of your entire small intestine. The camera sits inside a vitamin-sized capsule, which you swallow. As the capsule travels through your digestive tract, the camera takes thousands of pictures that are transmitted to a recorder.

If your doctor suspects you have dermatitis herpetiformis, he or she might take a small sample of skin tissue to examine under a microscope (skin biopsy).

A strict, lifelong gluten-free diet is the only way to manage celiac disease. Besides wheat, foods that contain gluten include:

• Barley
• Bulgur
• Durum
• Farina
• Graham flour
• Malt
• Rye
• Semolina
• Spelt (a form of wheat)
• Triticale

A dietitian who works with people with celiac disease can help you plan a healthy gluten-free diet. Even trace amounts of gluten in your diet can be damaging, even if they don't cause signs or symptoms.

Gluten can be hidden in foods, medications and nonfood products, including:

• Modified food starch, preservatives and food stabilizers
• Prescription and over-the-counter medications
• Vitamin and mineral supplements
• Herbal and nutritional supplements
• Lipstick products
• Toothpaste and mouthwash
• Communion wafers
• Envelope and stamp glue
• Play dough

Removing gluten from your diet will gradually reduce inflammation in your small intestine, causing you to feel better and eventually heal. Children tend to heal more quickly than adults.

Vitamin and mineral supplements

If your anemia or nutritional deficiencies are severe, your doctor or dietitian might recommend that you take supplements, including:

• Copper
• Folate
• Iron
• Vitamin B-12
• Vitamin D
• Vitamin K
• Zinc

Vitamins and supplements are usually taken in pill form. If your digestive tract has trouble absorbing vitamins, your doctor might give them by injection.

Follow-up care

Medical follow-up at regular intervals can ensure that your symptoms have responded to a gluten-free diet. Your doctor will monitor your response with blood tests.

For most people with celiac disease, a gluten-free diet will allow the small intestine to heal. For children, that usually takes three to six months. For adults, complete healing might take several years.

If you continue to have symptoms or if symptoms recur, you might need an endoscopy with biopsies to determine whether your intestine has healed.

Medications to control intestinal inflammation

If your small intestine is severely damaged or you have refractory celiac disease, your doctor might recommend steroids to control inflammation. Steroids can ease severe signs and symptoms of celiac disease while the intestine heals.

Other drugs, such as azathioprine (Azasan, Imuran) or budesonide (Entocort EC, Uceris), might be used.

Treating dermatitis herpetiformis

If you have this skin rash, your doctor might recommend a medication such as dapsone, taken by mouth, as well as a gluten-free diet. If you take dapsone, you'll need regular blood tests to check for side effects.

Refractory celiac disease

If you have refractory celiac disease, your small intestine won't heal. Then you'll likely need to be evaluated in a specialized center. Refractory celiac disease can be quite serious, and there is currently no proven treatment.

If you've been diagnosed with celiac disease, you'll need to avoid all foods that contain gluten. Ask your doctor for a referral to a dietitian, who can help you plan a healthy gluten-free diet.

Read labels

Avoid packaged foods unless they're labeled as gluten-free or have no gluten-containing ingredients, including emulsifiers and stabilizers that can contain gluten. In addition to cereals, pastas and baked goods, other packaged foods that can contain gluten include:

• Beers, lagers, ales and malt vinegars
• Candies
• Gravies
• Imitation meats or seafood
• Processed luncheon meats
• Rice mixes
• Salad dressings and sauces, including soy sauce
• Seasoned snack foods, such as tortilla and potato chips
• Seitan
• Self-basting poultry
• Soups

Pure oats aren't harmful for most people with celiac disease, but oats can be contaminated by wheat during growing and processing. Ask your doctor if you can try eating small amounts of pure oat products.

Allowed foods

Many basic foods are allowed in a gluten-free diet, including:

• Eggs
• Fresh meats, fish and poultry that aren't breaded, batter-coated or marinated
• Fruits
• Lentils
• Most dairy products, unless they make your symptoms worse
• Nuts
• Potatoes
• Vegetables
• Wine and distilled liquors, ciders and spirits

Grains and starches allowed in a gluten-free diet include:

• Amaranth
• Buckwheat
• Corn
• Cornmeal
• Gluten-free flours (rice, soy, corn, potato, bean)
• Pure corn tortillas
• Quinoa
• Rice
• Tapioca
• Wild rice

It can be difficult, and stressful, to follow a completely gluten-free diet. Here are some ways to help you cope and to feel more in control.

• Get educated and teach family and friends. They can support your efforts in dealing with the disease.
• Follow your doctor's recommendations. It's critical to eliminate all gluten from your diet.
• Find a support group. You might find comfort in sharing your struggles with people who face similar challenges. Organizations such as the Celiac Disease Foundation, Gluten Intolerance Group, the Celiac Support Association and Beyond Celiac can help put you in touch with others who share your challenges.

You might be referred to a doctor who treats digestive diseases (gastroenterologist). Here's some information to help you prepare for your appointment.

What you can do

Until your appointment, continue eating a normal diet. Cutting gluten before you're tested for celiac disease can change the test results.

Make a list of:

• Your symptoms, including when they started and whether they've changed over time
• Key personal information, including major stresses or recent life changes and whether anyone in your family has celiac disease or another autoimmune condition
• All medications, vitamins or supplements you take, including doses
• Questions to ask your doctor

For celiac disease, questions to ask your doctor include:

• What's the most likely cause of my symptoms?
• Is my condition temporary or long term?
• What tests do I need?
• What treatments can help?
• Do I need to follow a gluten-free diet?

Don't hesitate to ask other questions.

What to expect from your doctor

Your doctor is likely to ask you questions, including:

• How severe are your symptoms?
• Have they been continuous or occasional?
• What, if anything, seems to improve your symptoms?
• What, if anything, seems to worsen your symptoms?
• What medications and pain relievers do you take?
• Have you been diagnosed with anemia or osteoporosis?