Home / Diseases / Allergies



It has been proven that up to 70% of patients with some type of respiratory allergy to pneumonoallergens or food may develop Central Sensitivity Syndrome. Our Research Unit is studying this close relationship. It is important to point out that the same patient may present different types of mechanisms by which a food feels bad, that is, a coeliac may develop an allergy, or an allergic person may develop a food sensitivity, and a lactose intolerant person may develop a coeliac condition.

According to the current international classification of adverse reactions to food, they can be classified into two large groups, those with an immunological basis and those that do not have an immunological basis, commonly known as intolerances.


1. Food allergy

Adverse reaction after ingesting food with an immunological basis. Two mechanisms are involved: on the one hand, the binding of IgE antibodies to the proteins in the food and, on the other hand, the reactions produced by a cellular immune response to the food.

Sensitisation” is when it can be demonstrated that IgE antibodies to a food are present, but this is not equivalent to having allergic symptoms, and is therefore different from a true “food allergy”.

2. Celiac Disease

More commonly known as celiac’s. It is an immune-based adverse reaction characterised by chronic inflammation of the intestine caused by exposure to gliadin, a vegetable protein found in some dietary cereals. Gliadin is one of the components of gluten (protein present in wheat, rye, barley and oats).

When gliadin is ingested, the immune system produces IgA antibodies to gluten proteins that cross react with proteins in the intestinal epithelium of the small intestine, causing an inflammatory reaction that results in atrophy of the villi that line the intestine, interfering with the absorption of nutrients.


1. Lactose intolerance

Lactose intolerance is a non-immunological, enzyme-based adverse food reaction. It affects the intestinal villi because the body produces little or none of the enzyme lactase, making it impossible to properly metabolize lactose or “milk sugar”. It can be a congenital or acquired disease and in turn temporary or permanent.

In some cases, genetic inheritance is very important. The symptoms usually occur after the ingestion of milk or products that contain it, the most frequent symptoms being colic, abdominal swelling, flatulence and diarrhoea, which can lead to malnutrition in some individuals.

2. DAO deficit

In this case there is an alteration or inhibition of the intestinal and hepatic DAO, which makes it unable to eliminate the excess histamine from the patient’s diet, causing histamine accumulation. Several causes may affect the functioning of this enzyme, such as:

  • Chemical inhibition of DAO (drugs, alcohol, detergents, pesticides, among others).
  • Decrease in useful intestinal surface area (large surgical excisions, radiotherapy, chemotherapy, inflammatory bowel disease, among others).
  • Liver failure.

Patients with pathology of the digestive tract can present transitory deficits of DAO and other enzymes of the digestive mucosa. Recent studies have shown that DAO can be a good marker for assessing some inflammatory bowel diseases such as ulcerative colitis.

By continuing to use this site you agree to the use of cookies. More info

The cookie settings on this website are set to "allow cookies" to give you the best browsing experience possible. If you continue to use this website without changing your cookie settings or you click "Accept" below then you are consenting to this.