Celiac Disease: An Introduction

Symptoms and Associated Conditions That Usually Respond to a Gluten-Free Diet^6,7

• Diarrhea
• Fecal urgency or incontinence (soiling (stool) accidents)
• Abdominal bloating
• Abdominal discomfort/pain
• Excess gas
• Constipation
• Fatty stools
• Nutritional deficiencies, such as protein, calories, iron, calcium, vitamin D, B vitamins, vitamins A, E, and K, zinc and other minerals
• Dermatitis herpetiformis
• Canker sores (aphthous ulcers)
• Angular cheilitis (cracks at the corners of the mouth)
• Abnormally high liver enzymes on blood testing
• Anemia from deficiency of iron, B12, and/or folic acid (in the absence of other GI manifestations)

These conditions should respond to the gluten-free diet (GFD) when they are caused by celiac disease. CD may coexist with other conditions, such as small intestinal bacterial overgrowth, other food intolerances or irritable bowel syndrome. Symptoms such as diarrhea, abdominal bloating, gas, and constipation can persist despite a GFD.⁵ These other diagnoses should be reviewed by your gastroenterologist if your symptoms persist after one year on the GFD.

Symptoms and Associated Conditions That Sometimes Respond to a Gluten-Free Diet

• Lactose intolerance
• Fructose malabsorption
• Heartburn
• Microscopic colitis
• Reduced function of the spleen
• Fatigue
• Depressed mood
• Poor concentration
• Alopecia (hair loss)
• Follicular keratosis
• Dental enamel loss
• Short stature
• Thinning of the bones (osteoporosis and osteopenia)
• Joint pains
• Reduced fertility (men and women)
• Recurrent miscarriages

Symptoms and Associated Conditions That Are Not Expected To Respond to a Gluten-Free Diet

• Small intestinal bacterial overgrowth
• IgA deficiency
• Lupus (SLE)
• Poor coordination (cerebellar ataxia)
• Tingling and numbness of hands and feet (peripheral neuropathy)
• Seizure disorder
• Patches of depigmentation (vitiligo)
• Primary biliary cirrhosis
• Autoimmune hepatitis
• Rheumatoid arthritis
• Type 1 diabetes
• Thyroid disease
• Addison’s disease
• IgA nephropathy (inflammation in the kidneys)
• Fibrosing alveolitis (fine scarring in the air sacs of the lungs)
• Pulmonary hemosiderosis (bleeding in the lungs)
• Lung cavities
• Inflammatory bowel disease (IBD)

Inflammatory bowel diseases (Crohn’s, Ulcerative Colitis) are more often found among individuals with celiac disease; it may be because celiac disease testing at diagnosis and follow-up may help to uncover a more rapid diagnosis of concurrent IBD.

Celiac disease is a genetic, immune-mediated disease triggered by the ingestion of gluten. The individual makes antibodies called auto-antibodies and has an inflammatory reaction that attacks and damages the lining of the small intestine.

Non-celiac gluten sensitivity (NCGS) is a recently described condition with symptoms like those in celiac disease. Unlike CD, there is no genetic susceptibility to NCGS and there is no direct damage of the lining of the small intestine. It is also less associated with other autoimmune diseases.^5-8 Even though the small intestine is normal, an immune reaction triggered by gluten may be the cause of NCGS.^9,10 Extra-intestinal manifestations such as fatigue, neurological and psychiatric symptoms, joint pain and “foggy mind” may be seen in both NCGS and CD.¹¹ Symptoms improve or even disappear after withdrawing gluten from their diet.¹² As a result, many patients with NCGS will try a GFD on their own.

NCGS is a diagnosis of exclusion. This means that your doctor will only give you a diagnosis of NCGS if both CD and a gluten or wheat allergy have been ruled out. However, whether this is a life-long condition and to what degree gluten should be avoided is currently being studied. Until new data arrives, people with NCGS should do whatever they feel offers them the best quality of life overall.

A gluten or wheat allergy involves an adverse immune response to the gluten or other wheat (cereal) proteins that leads to symptoms such as swelling around the mouth, hives, sneezing and stomach discomfort. Damage to the small intestine, however, is mild and usually short-lived.¹³ Some symptoms are the same as in celiac disease, but an allergy can, at times, result in immediate and life-threatening symptoms.

There are four main categories of celiac disease^1,14:

Classical Celiac Disease

Classical celiac disease is characterized primarily by gastrointestinal problems such as diarrhea, weight loss and abdominal pain or nutritional problems due to malabsorption. A biopsy of the small intestine will show villous atrophy (damage). Improvement of this damage will usually be seen on the gluten-free diet. Symptoms should also improve on a gluten-free diet.

Non-Classical Celiac Disease

There are few or no gastrointestinal symptoms presented in non-classical celiac disease. Non-gastrointestinal features, such as Dermatitis Herpetiformis (a very itchy skin rash), iron deficiency anemia, or osteoporosis are more common. Other examples include fertility issues, unexplained high liver enzymes, unexplained headaches, movement disorders (ataxia), and tingling in the hands and feet (polyneuropathy). Like classical celiac disease, the diagnosis is made by blood testing for antibodies commonly found in CD. Damage is seen in the small intestinal biopsy and symptoms improve on a GFD. The 'atypical' presentation of celiac disease is currently the most common one.

Subclinical Celiac Disease

Similar terms are silent celiac disease and asymptomatic celiac disease. Subclinical celiac disease is celiac disease but does not have any of the symptoms or other abnormal lab values, except for positive circulating antibodies.¹⁴ As such, there are no related gastrointestinal or non-gastrointestinal symptoms or nutritional deficiencies seen. Damage still occurs to the small intestine, however. Individuals with subclinical CD are usually found through screenings of high-risk individuals. Examples include a person with a family history of CD or type 1 diabetes, or someone diagnosed on routine endoscopy that was done for other reasons. A gluten-free diet is still recommended among asymptomatic individuals who have intestinal damage to prevent future problems (from malabsorption, osteoporosis, and infertility).

Potential Celiac Disease

People with a normal small intestinal mucosa who are at increased risk of developing celiac disease as indicated by positive celiac disease serology.¹⁴ Blood tests are positive for celiac antibodies (either endomysial antibody or tissue transglutaminase antibody). The small intestinal biopsy is normal with no evidence of villous atrophy. Individuals with potential CD may develop active CD later in life, either with symptoms or changes in their small intestinal biopsies. When asymptomatic and without nutritional deficiencies, the values of treating potential CD with a GFD is unproven. Most doctors recommend to stay on a normal diet but with increased awareness that active CD may develop over time.¹⁴

Celiac disease tends to run in families because people who have celiac disease inherited the genes and may be exposed to similar environmental risks. CD can begin at any time, or not at all, during a person's life because of certain environmental factors.

To develop celiac disease, you must have genetic markers of either HLA DQ2, HLA DQ8 or both of these genes. For this reason, we screen for CD among your family members since they may have inherited the genes and have one of the many forms of CD. However, having the genes alone is not enough to develop the disease.

Other required conditions are:

1. The person must have been exposed to gluten (such as when a baby is given wheat cereal as infant food).
2. Environmental or physiological (having to do with the body) factors may also contribute to the onset of celiac disease.

Environmental or physiological (bodily) factors include surgery, pregnancy, childbirth, and gastrointestinal infections, especially viral or severe emotional stress.¹⁴ Researchers are also looking into other factors that may influence the symptoms of CD including cow's milk formulas, breastfeeding, age at gluten introduction, quantity of gluten, quality of cereals, and use of probiotics.^16,17

In all humans, gluten is not completely digested. If someone has celiac disease, eating gluten results in an increase in intestinal permeability (leaky gut) and the immune system damages the villi (fingerlike hairs) which line the small intestine.¹ These villi take in nutrients from food and move them into the bloodstream where the body can use them. Without enough healthy villi, a person will not get enough of the nutrients he/she needs.¹⁸ Most of the time, antibodies (anti-deamidated gliadin peptides [DGP]) are also made against gluten. Other antibodies are made against tissue transglutaminase, a common enzyme in the intestinal lining. These antibodies are detected with blood tests.

• We do not recommend making changes to your diet before consulting a physician. Always speak to your doctor if you have any symptoms that concern you.

• It is important to have a medical evaluation of celiac disease before starting a gluten-free diet. Once on the diet, the common tests including biopsy of the intestine will start to heal and this will make it difficult to make a diagnosis.³

• The longer a person goes without a diagnosis and untreated, the greater the chance of developing long-term medical problems.¹⁹

• Once a diagnosis of celiac disease is made, screening for silent manifestations can take place and thus detect conditions related to the disease, such as osteoporosis and vitamin and mineral deficiencies such as iron, folate and vitamin D deficiency. The duration of gluten exposure does correlate with the risk of developing associated autoimmune diseases. Therefore, early diagnosis is preferable.²⁰