Celiac Disease 101: What Causes It, How It’s Diagnosed, and How to Manage It

Celiac disease is a commonly underdiagnosed autoimmune condition that can have a significant impact on long-term health.

If you've ever wondered whether gluten could be contributing to your symptoms—or you're simply trying to better understand —this guide breaks down the basics in a clear, approachable way.

From causes and symptoms to diagnosis and living gluten-free, here's what you need to celiac diseaseknow.

What Is Celiac Disease?

Celiac disease (also spelled coeliac disease) is a chronic autoimmune disorder triggered by eating gluten, a protein found in wheat, barley, and rye.

When a person with celiac disease consumes gluten, their immune system reacts in a way that damages the lining of the small intestine. In particular, it can damage the villi—tiny, finger-like structures responsible for helping the body absorb nutrients.

Over time, this damage can lead to inflammation, poor nutrient absorption, deficiencies, and symptoms that may affect much more than the digestive system.

A Few Important Facts About Celiac Disease

• Celiac disease is not a food allergy.

• It is different from non-celiac gluten sensitivity.

• It can develop at virtually any age, including adulthood.

• Gluten can be found in obvious foods as well as less obvious sources, including certain medications, supplements, and personal-care products. For people with celiac disease, the primary concern is gluten that can be ingested.

What Causes Celiac Disease?

There isn't one single cause of celiac disease. Instead, it appears to develop through a combination of genetic susceptibility and environmental factors.

1. Genetics

Most people with celiac disease carry genetic variants known as HLA-DQ2 or HLA-DQ8.

Having one of these genetic variants does not mean that a person will definitely develop celiac disease. However, their absence makes celiac disease much less likely.

2. Environmental Factors

Celiac disease may become apparent at different points in a person's life. Researchers continue to study the role of environmental factors and events such as infections and other physiological stressors in the onset of the disease.

3. Early-Life Factors

Researchers have also investigated whether factors such as the gut microbiome, early feeding patterns, infections, and other early-life exposures may influence the development of celiac disease in genetically susceptible individuals.

Research in this area continues to evolve.

What Happens in the Body?

Gluten contains proteins called gliadins and glutenins. In people with celiac disease, exposure to gluten triggers an abnormal immune response.

This immune response causes inflammation and damages the lining of the small intestine.

As the intestinal villi become damaged and flattened, the small intestine becomes less effective at absorbing nutrients.

This can contribute to:

• Nutritional deficiencies

• Digestive problems

• Anemia

• Fatigue

• Bone-health concerns

• Neurological symptoms

• Other complications when celiac disease remains untreated

This is one reason celiac disease can affect the whole body, not simply digestion.

Symptoms of Celiac Disease

Celiac disease can present in many different ways. Some people experience significant gastrointestinal symptoms, while others have symptoms that don't immediately appear related to digestion.

Some people may have few or no noticeable symptoms despite intestinal damage.

Common Symptoms May Include:

• Abdominal pain

• Diarrhea

• Constipation

• Bloating and gas

• Unexplained weight loss

• Iron-deficiency anemia

• Chronic fatigue

• Joint or muscle discomfort

• Headaches or migraines

• Brain fog

• Mood changes

• Dermatitis herpetiformis, an intensely itchy skin rash associated with celiac disease

• Fertility or reproductive concerns

Other Possible Signs May Include:

• Abdominal distention

• Changes involving the tongue or corners of the mouth associated with nutritional deficiencies

• Peripheral edema or swelling

• Neuropathy, including numbness or tingling

• Skin changes or rashes

Because the symptoms can be so varied, some individuals live with celiac disease for years before receiving a diagnosis.

How Is Celiac Disease Diagnosed?

If you suspect you may have celiac disease, it's important to speak with your healthcare provider before eliminating gluten from your diet.

Celiac testing is generally most accurate while a person is still consuming gluten. Beginning a gluten-free diet before testing may affect test results and make diagnosis more difficult.

1. Blood Tests

Healthcare providers may begin with antibody testing. Tests can include:

• tTG-IgA — tissue transglutaminase IgA

• Total serum IgA

• EMA-IgA — endomysial antibody IgA

• DGP antibodies — deamidated gliadin peptide antibodies in certain situations

Your healthcare provider will determine which tests are appropriate based on your individual circumstances.

2. Genetic Testing

Testing for HLA-DQ2 and HLA-DQ8 may sometimes be used when the diagnosis is unclear.

Because many people without celiac disease also carry these genes, a positive genetic result does not confirm celiac disease. However, a negative result can make the diagnosis much less likely.

3. Endoscopy and Biopsy

For many adults, an upper endoscopy with biopsies of the small intestine is used to confirm a diagnosis.

During this procedure, small tissue samples are collected and examined for changes associated with celiac disease, including damage to the intestinal villi.

Managing Celiac Disease

There is currently no cure for celiac disease.

The cornerstone of treatment is a strict, lifelong gluten-free diet.

Removing gluten allows the small intestine to begin healing and can significantly improve symptoms and nutrient absorption.

How Long Does Healing Take?

Some people notice improvement in their symptoms within weeks of eliminating gluten.

Complete intestinal healing can take considerably longer and varies depending on factors such as age, severity of intestinal damage, nutritional status, and how consistently gluten is avoided.

Follow-up care with a healthcare professional is important to monitor recovery.

Nutrition After a Celiac Diagnosis

A gluten-free diet doesn't have to mean relying entirely on packaged foods labeled "gluten-free."

Many nutritious whole foods are naturally free from gluten.

Naturally Gluten-Free Choices Include:

• Fruits and vegetables

• Rice

• Quinoa

• Buckwheat

• Millet

• Potatoes and other tubers

• Beans and legumes

• Nuts and seeds

• Eggs

• Unprocessed meat, poultry, and fish

Some people with newly diagnosed celiac disease may temporarily have difficulty digesting lactose because of intestinal damage. This often improves as the intestine heals, although individual needs vary.

Your healthcare provider may also test for nutritional deficiencies and recommend supplementation when necessary. Common nutrients monitored can include iron, folate, vitamin B12, vitamin D, calcium, and other vitamins and minerals.

Watch for Hidden Sources of Gluten

Learning to identify gluten is an important part of successfully managing celiac disease.

Gluten may appear in unexpected places, including:

• Sauces and gravies

• Seasoning blends

• Processed foods

• Supplements

• Certain medications

• Foods prepared on shared equipment

Cross-contact matters, too.

For someone with celiac disease, even small amounts of ingested gluten can be problematic. Shared toasters, cutting boards, cooking utensils, fryers, and food-preparation surfaces may introduce gluten into otherwise gluten-free foods.

Learning to read labels and prevent cross-contact becomes an important part of everyday life.

Possible Complications of Untreated Celiac Disease

When celiac disease remains untreated, ongoing intestinal damage and nutrient malabsorption can increase the risk of health complications.

These may include:

• Osteopenia or osteoporosis

• Iron-deficiency anemia and other nutritional deficiencies

• Fertility and reproductive problems

• Neurological complications

• Certain additional autoimmune conditions

• Rare but serious intestinal complications

Early diagnosis and consistent treatment can help reduce many of these risks.

Celiac Disease vs. Wheat Allergy vs. Gluten Sensitivity

These conditions are often grouped together, but they are not the same thing.

Celiac Disease

Celiac disease is an autoimmune disorder. Consuming gluten triggers an immune response that damages the small intestine.

Wheat Allergy

A wheat allergy is an allergic immune response to proteins found in wheat. Symptoms can include hives, swelling, respiratory symptoms, digestive symptoms, and in severe cases, anaphylaxis.

Non-Celiac Gluten Sensitivity

People with non-celiac gluten sensitivity may experience symptoms associated with eating gluten-containing foods but do not have the characteristic autoimmune intestinal damage seen in celiac disease.

Because symptoms can overlap, proper medical evaluation is important rather than attempting to diagnose the condition yourself.

Celiac Disease and Hashimoto's Thyroiditis

Celiac disease is associated with an increased prevalence of certain other autoimmune conditions, including autoimmune thyroid disease such as Hashimoto's thyroiditis.

If you already have an autoimmune condition—or have a close family member with celiac disease—talk with your healthcare provider about whether screening for celiac disease may be appropriate.

Living Well With Celiac Disease

Receiving a celiac diagnosis can initially feel overwhelming. Suddenly, grocery shopping, dining out, traveling, and even preparing meals at home may require more planning.

But living gluten-free becomes easier with education and experience.

Focus on:

• Learning how to read food labels

• Choosing naturally gluten-free whole foods

• Preventing cross-contact

• Asking questions when dining away from home

• Monitoring nutritional health

• Maintaining regular follow-up with your healthcare team

With the right knowledge and support, people with celiac disease can live healthy, active, and fulfilling lives.

Final Thoughts

Celiac disease is about much more than avoiding bread or following a dietary trend. It is a chronic autoimmune condition that requires appropriate diagnosis and lifelong management.

The encouraging news is that once celiac disease is properly identified, a strict gluten-free diet can allow the intestine to heal, improve symptoms, correct many nutritional deficiencies, and reduce the risk of future complications.

If you're experiencing unexplained digestive problems, chronic fatigue, anemia, skin changes, neurological symptoms, or other persistent concerns, consider discussing celiac disease with your healthcare provider.

And remember: if you're planning to be tested for celiac disease, speak with your healthcare provider before removing gluten from your diet.

This article is provided for educational purposes and is not intended to diagnose, treat, cure, or prevent any disease. Always consult a qualified healthcare professional regarding symptoms, testing, dietary changes, supplements, or medical treatment.

References & Further Reading

• American Autoimmune Related Diseases Association (AARDA). (2019). Celiac Disease.

• Beyond Celiac. (2019). Celiac Disease and Thyroid Disease.

• Caja, S., Mäki, M., Kaukinen, K., & Lindfors, K. (2011). Antibodies in celiac disease: Implications beyond diagnostics.

• Ciacci, C., et al. (2004). Allergy prevalence in adult celiac disease.

• Greco, F., & Sather, R. (2018). Anti-tissue Transglutaminase Antibody.

• Holtmeier, W., & Caspary, W. F. (2006). Celiac disease.

• Kupper, C. (2005). Dietary guidelines and implementation for celiac disease.

• Norris, J. M., et al. (2005). Risk of celiac disease autoimmunity and timing of gluten introduction.

• Parzanese, I., et al. (2017). Celiac disease: From pathophysiology to treatment.

• Pelkowski, T., & Viera, A. (2014). Celiac Disease: Diagnosis and Management.

• Romanos, J., et al. (2009). Analysis of HLA and Non-HLA Alleles Can Identify Individuals at High Risk for Celiac Disease.

• Rubio-Tapia, A., & Murray, J. A. (2010). Celiac disease.

• University of Chicago Celiac Disease Center. Antibody Blood Tests.