Celiac disease is an autoimmune disease that prevents the proper digestion and absorption of gluten.
Gluten is a group of proteins known as prolamins and glutelins found in cereal grains (wheat and its varieties: rye, barley, and triticale).
Oats also contain a type of gluten.
If you have celiac disease and eat food containing gluten, your immune system will begin to attack the lining of your small intestine.
As a result, people with celiac disease have an inflamed and irritated intestine, which can prevent proper absorption of nutrients — leading to other health complications.
Both children and adults can have celiac disease — the signs and symptoms often differ between the two. In adults, celiac disease can cause:
- Diarrhea or constipation
- Gas and bloating
- Stomach pain, nausea, and vomiting
- Unexplained weight loss
Adults with celiac disease may also experience symptoms not related to the digestive system:
- Canker sores (mouth ulcers)
- Brain fog
- Joint and muscle aches
Symptoms of celiac disease in children can include:
- Chronic diarrhea
- Swollen abdomen
- Nausea and vomiting
Nutritional malabsorption may lead to other symptoms, including:
- Inability to develop at a healthy rate (failure to thrive)
- Impaired growth
- Weight loss
- Tooth enamel loss
- Delayed puberty
Dermatitis herpetiformis (DH) are patches of itchy, red bumps, or blisters. Typically, DH occurs on the forearms, elbows, around the knees, and on the buttocks.
It can also occur around the hairline. DH affects around 10% of people with celiac disease. (NIH NIDDK, 2014)
This condition occurs from deposits of immunoglobulin A (IgA) in the skin. The presence of IgA triggers an immunologic reaction, which results in the development of skin lesions.
Causes and Risk Factors
Medical experts are not entirely sure what causes celiac disease. Many researchers believe that this condition involves a range of factors, including:
Your genes play a crucial role in celiac disease. You must have one of the two genes associated with this condition to develop it. Otherwise your chances of ever developing celiac disease are very slim.
These genes are the variants of the HLA-DQA1 and HLA-DQB1 genes. (NIH NLM Genetics Home Reference, 2019)
Although 40% of the American population have these genes, not all of them have celiac disease. Other causative factors are also involved. (Offord, 2017)
Diet is another factor involved in the development of celiac disease. Gluten triggers an immune response to attack your small intestine. This causes damage to the intestinal lining and can lead to malabsorption of nutrients.
The surrounding environment
Environmental factors are thought to be another leading contributor to celiac disease, though how these factors play a role is not clear.
For example, some people may have consumed foods containing gluten for several years and then suddenly developed symptoms of celiac disease.
In other cases, very young children show symptoms of celiac disease as soon as foods containing gluten are introduced into their diets. Some women begin experiencing symptoms of celiac disease soon after pregnancy or birth. Others notice symptoms after a severe illness, such as a viral infection.
Risk factors include having a directly related family member with celiac disease, or having one of the following conditions:
- Down’s syndrome
- Type 1 diabetes
- Lymphocytic colitis
- Turner syndrome
- Addison's disease
- Hashimoto’s disease
Physicians use a two-step process to diagnose celiac disease.
Step one: Screening
For the screening process, your doctor will take a blood test to measure certain antibodies in your blood.
People with celiac disease — who have gluten-containing foods in their diet — have higher levels of the tissue transglutaminase IgA antibody and the IgA antibody. (Celiac Disease Foundation, n.d.)
The body’s immune system produces these antibodies in response to gluten, which it perceives as a threat. For this reason, you must still be consuming gluten for this test to be accurate.
Recommendations for screening
Medical experts recommend that the following people should get screened for celiac disease:
- Children aged three years older who experience the symptoms listed above.
- Immediate relatives of people who have been diagnosed with celiac disease.
- Anyone who suffers from one of the disorders listed above under risk factors or who has some of the symptoms listed above
Screening tests for celiac disease
There are several types of test used for screening celiac disease. These include:
- tTG-IgA Test: This test is considered to be the most accurate means of screening for celiac disease. For children around three years or younger, screening should also include tests for IgG and deamidated gliadin IgA (DGP) antibodies. The tTG-IgA test’s specificity is 95%. (Celiac Disease Foundation, n.d.)
- IgA Endomysial antibody (EMA): Although this test is not as sensitive as the tTG-IgA test, its specificity is close to 100%. This test is typically only used in cases of celiac disease which are difficult to diagnose. This is because it is expensive and requires the use of tissue from an umbilical cord.
- Total serum IgA: This type of screening may be used to test for IgA deficiency. If you have an IgA deficiency, this can cause a false negative result in a tTG-IgA or EMA test. If you test positive for IgA deficiency, your doctor will order a tTG-IgG or a GPD test.
- Genetic testing: Genetic screening tests for the gene variants HLA-DQ2 and HLA-DQ8. One or both of these must be present. People without these gene variants may develop celiac disease, but this is extremely rare. This test may help to rule out celiac disease, but it cannot rule it in, since many people with the genes do not develop celiac disease.
Step two: Diagnosis
After screening, diagnosis of celiac disease is confirmed using an intestinal biopsy. The biopsy is performed during a gastrointestinal endoscopy — a low-risk procedure.
You will need to prepare for the endoscopy by avoiding food and drinks for 8-10 hours before the procedure. Your doctor may also tell you to stop taking certain medications — such as blood thinners — until after the endoscopy.
You will be given a mild sedative before the procedure, and you will lie on your side for the duration of the endoscopy. The scope will be passed through your mouth and down your throat until the tube reaches your small intestine. Once there, a small tool attached to the tube will be used to take multiple samples of the intestinal lining.
After the endoscopy, the samples are sent to a laboratory. There, they are examined to assess damage to the villi — small, finger-like structures that help with the absorption and digestion of nutrients.
If they are flattened or damaged, this is typically a sign of celiac disease. The pathologist will assign what’s known as a “Modified Marsh Type” to the biopsy findings. This will determine the diagnosis.
Diagnosis of Dermatitis Herpetiformis (DH)
If you show signs and experience symptoms of DH, your doctor will usually recommend a skin biopsy, where a small sample of skin is taken and sent to the lab.
This is sufficient for a diagnosis of both DH and celiac disease as the positive finding of the IgA antibody in the skin is considered a definitive indicator of celiac disease.
If the test comes back positive, you will not need an intestinal biopsy to confirm celiac disease. However, this test cannot rule out celiac disease since not everyone with celiac disease will also have DH.
Treatment of Celiac Disease
Once a diagnosis of celiac disease has been confirmed, your doctor will recommend a gluten-free diet. You may find this challenging at first, but with proper assistance from a nutritionist, you will likely adjust well.
You can still enjoy a delicious and nutrient-rich diet without eating foods containing gluten.
To resolve your celiac symptoms, you must follow a completely gluten-free diet. Most people notice improvement within just a few weeks of eliminating gluten from your diet. Typically, in young children with celiac disease, any intestinal damage will heal completely. For adults, even though symptoms may resolve, healing may not be complete.
There is no cure for celiac disease. This means that if you are a sufferer, and you want to stay healthy, maintaining a gluten-free diet is a life-long necessity. Even if you only consume a very small amount of foods containing gluten and don’t notice any symptoms, this can still cause further damage to your small intestine.
Foods to Avoid
A gluten-free diet eliminates all food containing any of the following, including all products derived from them:
- Wheat and its varieties
You can easily replace gluten-containing foods with gluten-free pasta and bread, which typically contain flour made from rice, soy, beans or potatoes.
It is important to note that some people with celiac disease may be sensitive to foods that do not contain gluten. This is known as Gluten Cross-Reactivity. The proteins in these foods may be mistaken for gluten by the immune system. These foods include dairy, corn, millet, oats, rice, and yeast.
What is a Non-celiac Gluten Sensitivity?
Non-celiac gluten sensitivity (NCGS) is a condition which causes certain people to have symptoms similar to those of celiac disease, such as:
- Stomach pains
- Gas and bloating
- Brain fog
However, non-celiac gluten sensitivity does not cause damage to the small intestine. Symptoms of non-celiac gluten sensitivity usually resolve when gluten is eliminated from the diet.
There are some sections of the scientific community that challenge whether NCGS exists. In some cases, the symptoms are a result of a problem digesting fructans, which is a type of fiber found in wheat and other grains.
If this is the case, then a low FODMAP diet, which removes these foods, is often helpful, along with the removal of all gluten-containing foods.
If you think you or a family member may have celiac disease, it’s essential to get screened as soon as possible to limit the extent of damage to the small intestine.