The celiac disease is a permanent dietary intolerance to gluten.

Gluten is a protein that is present in wheat and other cereals, such as barley, rye, emmer, kamut, spelt and triticale. In a genetically predisposed person of any age, the ingestion of even small quantities of foods containing gluten triggers an immune response in the small intestine, causing a chronic inflammation. This in turn causes the eventual disappearance of the intestinal villi. This process is accompanied by a range of symptoms that vary from person to person. In a healthy individual, the intestinal wall is covered with villi and microvilli, the function of which is to increase the surface area of the intestine to aid the absorption of nutrients. In the individual with celiac, however, these villi are greatly reduced and the mucous lining of the intestine is damaged. Because of the decrease in surface area, the absorption of nutrients such as protein, fats, carbohydrates, vitamins and minerals is inhibited, leading to malnutrition and loss of function. Gluten intolerance is one of the most common conditions worldwide. In countries with a population of primarily European origin (in Europe, North and South America and Australia), approximately one out of every 100 people is affected. A similar frequency has been reported in developing regions, such as North Africa, the Middle East and India, where large quantities of wheat are consumed.

Celiac disease has a complex pathology that is caused by a variety of hereditary and environmental factors.

Genetic factors
That celiac disease has a genetic component is demonstrated by the fact that family member are approximately ten times more likely than the general population to develop celiac disease.. However, not all of the numerous genes that contribute to a hereditary predisposition are presently known. The best-understood factors belong to the human leukocyte antigen (HLA) system, a complex of genes that “recognise” molecules foreign to the organism. The HLA-DQ2 and/or DQ8 genotypes are present in the vast majority (at least 95 per cent) of individuals with celiac disease. The presence of HLA-DQ2/DQ8 alone, however, does not necessarily lead to a development of the celiac disease, as these same genes are found in a high percentage of healthy people (20 to 3 0 per cent of the general population).

Environmental factors
The environmental component of the celiac diseaser is an exposure to gluten in the diet.

Further genetic dispositions and severe gastrointestinal infections (e.g. rotavirus) are frequently listed as additional factors which could be responsible for the occurrence of celiac disease.

The symptoms of celiac disease can vary. In some cases, a person may feel no symptoms at all.

The most common manifestations are diarrhea, weight loss and general weakening, abdominal bloating and abdominal pain, vomiting, and, in children, failure to grow. Other symptoms can manifest themselves outside the intestine, such as anemia, osteoporosis, amenorrhea and vitamin or mineral deficiencies. Some symptoms come from pathologies that are associated with celiac disease. Celiac disease does not always present itself in the same way, however; it has various clinical forms, and these must be taken into account during the diagnostic phase. The various clinical manifestations of celiac disease can be divided into typical cases with marked gastrointestinal symptoms (these cases are in the minority today) and the more frequent atypical cases, which are characterized by vague symptoms such as colitis (the so-called “irritable bowel”) or an iron deficiency that is resistant to oral iron therapy. There are also the silent forms, which are occasionally diagnosed in at risk populations (family members of individuals with celiac disease, for example, or diabetics who are subjected to serological screening) despite the absence of obvious symptoms. In such cases, the apparent lack of symptoms is misleading; often after the initiation of a gluten free diet, a marked improvement in overall well-being is noted. Finally, celiac disease is suspected in some patients because they have a non-intestinal complaint that may be associated with celiac disease, such as dermatitis herpetiformis, aphthous stomatitis, diabetes, osteoporosis, fertility disorder, thyroiditis, allergies, food intolerance, or a neurological pathology. In individual – fortunately very rare – cases, celiac disease manifests itself from the onset with severe complications such as ulcerative jejunoileitis or intestinal lymphoma.

There are four ways in which celiac disease manifests itself.

Due to the heterogeneous symptoms of celiac disease, there is a need to divide celiac disease into various clinical forms:

Typical celiac disease
The typical forms of celiac disease begin early, generally within a few months of the start of weaning, with symptoms of intestinal malabsorption: chronic diarrhea, failure to grow, lack of appetite, vomiting, and abdominal distension (“bloated belly”).

Atypical celiac disease
The atypical forms of celiac disease manifest themselves late with predominantly non-gastrointestinal symptoms, such as iron deficiency anemia, an increase in hepatic transaminase, recurring abdominal pains, dental enamel hypoplasia, dermatitis herpetiformis, or short stature in school aged children.

Silent celiac disease
The silent forms of celiac disease are diagnosed by chance in apparently healthy individuals as the result of an examination. Many cases are silent only in appearance; after beginning the gluten free diet, many people feel a marked improvement in psychological and physical wellbeing.

Potential celiac disease
Cases are defined as potential or latent if they present positive serological markers but normal intestinal biopsies. Patients with latent celiac disease, if left on an unrestricted diet, may in time develop a full-blown intestinal lesion. An elevated occurrence of the celiac disease, often in an insidious form, is found in individuals with other autoimmune conditions (especially insulin-dependent diabetes and thyroiditis), syndromic pathologies (Down’s syndrome, Turner’s syndrome and Williams syndrome), or a deficiency of serum immunoglobulin A (IgA).

Up to 1% of the population is affected.

Just 20 years ago, prevalence figures were stated as between 1:1000 to 1:2000. These data are based on the occurrence of manifest conditions and typical types of celiac disease.
The discovery of different celiac disease antibodies and the screening tests of recent years have shown that celiac disease is more common than had been assumed. The prevalence of celiac disease has been stated as between roughly 1:100 and 1:500 in various countries. This means that up to 1% of the population is affected by celiac disease, whereby most of the cases are asymptomatic i.e. do not display the typical progressive form of celiac disease and are therefore not diagnosed. It has been calculated that for every person who has been diagnosed with celiac disease there are seven to ten people with celiac disease who have not been diagnosed. The period between the occurrence of the first symptoms and the diagnosis of celiac disease can last up to seven years.

Serological investigations and a biopsy of the small intestine provide definitive diagnosis.

The diagnosis of celiac disease is based on four foundations:

• Anamnesis and clinical symptoms
• Serology
• Histology
• Improvement of the symptoms and response of the antibodies to the gluten-free diet
• It is important that both the serological tests and the small intestine biopsy are carried out BEFORE the start of a gluten-free diet.

A strict gluten-free diet as treatment.

The only solution/treatment for celiac condition is strict lifelong adherence to a gluten free diet.
Even the smallest amounts of gluten may damage the small intestine mucous membrane. Many of the most common foods may contain traces of gluten and therefore careful label reading is essential when shopping.
The transition to a gluten-free diet is made easier by the fact that there are many different gluten free products available for people with celiac disease (bread, pasta, cookies etc.) that are labelled gluten free.

You can find out more information on this topic in the section "A gluten-free diet"

Possible concomitant conditions and intolerances in the case of celiac disease

With a prevalence of 13.8%, autoimmune diseases are much more common in patients with celiac disease than in people without celiac disease. However, celiac disease is also associated with intolerances and other genetic, endocrinological and neurological conditions; we have provided a summary of the most common and most significant conditions.

Type 1 diabetes
We have known for years that celiac disease and type 1 diabetes often go hand in hand. The prevalence of celiac disease in type 1 diabetics is between 3 and 8%. Inversely, 3 to 6% of people with celiac disease have type 1 diabetes. The joint occurrence of the two conditions seems to be caused by a common genetic predisposition. In addition, there is evidence of increased zonulin levels in both type 1 diabetics and celiac patients. Zonulin is a protein which regulates intestinal permeability.
In view of the frequent association of the two pathologies, all type 1 diabetics should be put through screening for celiac disease via the determination tTG antibodies.

Lactose intolerance
Before and just after diagnosis it is possible that people with celiac disease will also develop a secondary lactose intolerance, which is triggered by the damage to the small intestine mucous membrane. As a result these individualss should follow a diet which is both gluten-free and lactose-free at the start of treatment. In the remission phase, the individual can usually tolerate lactose again.

Dermatitis herpetiformis (DH), Duhring's disease
DH is a very itchy rash. In 90% of the patients it occurs on the elbows and underarms. Other areas that are frequently affected include the buttocks and the front of the knee. DH is the "skin manifestation" of celiac disease. If an individual has been diagnosed with DH, this will automatically also involve celiac disease. The same is not always true in the reverse scenario. In many DH patients, celiac disease is not very pronounced and is usually only noticed when the patient develops the typical rash. The cause of this combination can be attributed to the identical genetic background.

Other autoimmune diseases
13.8%, autoimmune diseases frequently occur in combination with celiac disease. The autoimmune disease most frequently associated with celiac disease is certainly diabetes, but autoimmune thyroiditis (Hashimoto thyroiditis) and autoimmune liver diseases are also common.

Other concomitant conditions of celiac disease include:

• Selective IgA deficiency
• Sjörgen's syndrome
• Primary billiary cirrhosis
• Crohn's disease
• Down's syndrome
• Ullrich Turner syndrome
• Williams syndrome
• Epilepsy

After-effects may develop if coeliac condition is left untreated.

Most people with celiac disease report very quick response to a gluten-free diet. A lack of a response to a gluten-free diet can usually be attributed to conscious or accidental mistakes in the diet. Occasional and even frequent accidental ingestion of gluten considerably increases the risk of developing long-term consequences of celiac disease. Long-term consequences and complications of celiac disease may include:

• Osteoporosis
• Refractory celiac disease (lack of response to gluten-free nutrition)
• Malignant tumors (lymphoma, adenocarcinoma)
• Collagen sprue
• Ulcerations (ulcers in the intestine)

Routine and regular follow-up examinations are rocommended.

An individual with celiac disease should be monitored:

• 3 months after diagnosis
• 1 year after diagnosis
• Annually thereafter