Intestinal diseases and food intolerance   

The intestinal tract is one of the most important organs of the body. It is lined with a secretory and absorptive membrane responsible for the resorption of fluids and nutrition.This membrane has to be highly permeable and is therefore very susceptible for any kind of impairment.
Food, parasites, viruses, toxins and enzymes can cause an antigenic strain. Bacterial growth, there are 1014 bacteria in the gut, need a good balance to prevent overgrowth and endotoxin damage.

- Food intolerance and food allergy are terms often used to describe the same condition, 
  but they are literally two different things
- Food intolerance is a reaction that is caused by some metabolic disorder, for example
- actose intolerance
- carbohydrate intolerance
- aldolase deficiency
- histamine intolerance   (e.g. high concentrations in fish)

An allergy is an altered reactivity following a second or subsequent exposure to different antigens. A true food allergy (or hypersensitivity) is the reaction mediated through different immune mechanisms. Allergens get inhaled or digested and cause a response of the immune system. Genetic predisposition plays as well an important role as age and environmental factors. Clinical signs vary, but are typically gastrointestinal, with frequent diarrhoea containing mucus or blood. Further signs are an increased defecation rate, flatulence and vomitus and of course inflammatory bowel diseases such as eosinophilic colitis and lymphocytic-plasmacytic colitis

Diagnosis

Diagnosis of an adverse reaction to food is usually confirmed through the response to an exclusion or hypoallergenic diet. Although a wide range of commercial hypoallergenic diets are available, it is generally agreed that the most effective method of diagnosing an adverse reaction to food is through the response to a home prepared elimination or hypoallergenic diet
followed by test meal challenge. Usually it is necessary to feed the diet for at least 12 weeks. Owner compliance can be poor if the benefits are not rapidly apparent.Therefore serological allergy tests can be of an advantage to confirm the suspicion of a food hypersensitivity.

Food-allergy-test

This kind of test is successfully used in the United Kingdom for some years. In cats and dogs the diagnosis of a food hypersensitivity is therefore easily available.
Food allergen-specific IgE and IgG antibodies can be detected in one test. IgE is responsible for allergic reactions of the immediate type (type I), whereas IgG is commonly applied to reactions involving delayed (type IV) hypersensitivity.
Allergy test have normally a high negative predictable value. This means that a negative test result has a high likelihood that this foodstuff is not causing the clinical signs.
An other advantage is the chance to decrease the time to find the right diet.

Result

In 50% of the samples we tested at LABOKLIN a positive result of a food hypersensitivity could have been confirmed. In dogs with gastrointestinal problems the change of diet showed in nearly 80% of the cases a remarkable improvement of the clinical sings.Food-allergy-test (simultaneous detection of IgE and IgG) 

This test is species-specific and covers 90% of the relevant foodstuff in a cats or dogs diet.

Diagnostic procedures in diarrhoea of dogs and cats

1. Diagnostic of small intestine diarrhoea
   

Diagnostic of food allergy

Diagnostic of large intestine diarrhoea