Food allergy

The food allergy is a consecutive Allergie to the ingestion of usually inoffensive food Molécules.

The allergic demonstrations are:

local, giving place to gastro-intestinal symptoms: when the digestive Tract is the seat of the allergic reactions, the allergy is known as “digestive”.
distant, causing cutaneous and respiratory symptoms.

The classification suggested by the European Academy of Allergy and Clinical Immunology (1994) distinguishes within the unfavourable reactions to food “the toxic reactions and the nontoxic reactions”. The toxic reactions are dependant either on culinary processes or with contaminants. The nontoxic reactions can be immunological (see definition Immunologique) or not immunological. The food allergy or over-sensitiveness with food refers to the reactions implying of the immunological mechanisms.

Differences between the allergy and food intolerance

In the majority of the cases, a reaction known as “secondary” to the absorption of a food is not consequent with a food allergy but generally results from a Food poisoning, an aversion for a food or an intolerance to one or more ingredients.

The food allergy is regarded as a specific form of food intolerance. This one expresses by activation of immune system (absorption of protein in food accused - called Allergène - which causes a chain reaction in the immune system), leading to the release of Anticorps. The released antibodies involve in their turn the release of other molecules, persons in charge of the symptoms in the form of expressed immediate (like respiratory problems) or expressed delayed (cutaneous reactions for example).

Food intolerance relates to the pharmacological, metabolic Réactions and poisons where the Immune system does not play any part.

Prevalence

The majority of the individuals eat a large variety of food without incurring the least risk. For a small percentage of the population, however, specific food or components can cause secondary reactions going from a light redness to a severe allergic answer.

These secondary food reactions can be due to an allergy or a food intolerance. A person on three estimates herself allergic to certain food. In the children, the frequency of the allergy is more frequent.

Food allergens

The nature of food implied in the food allergy varies according to the dietary habits of the countries but especially, transcending those, according to the age. If 50% of the food allergies are of vegetable origin and 50% of animal origin, in the child in fact especially the animal Allergènes are implied, gradually replaced by the vegetable allergens.

Diagnosis of the food allergy

Antecedents

A family Atopie (Eczema, Urticaria, Asthma, allergic Rhinitis) is found, according to the statistics, with a frequency reaching 70% of the children allergic to the PLV. Early food diversification seems to increase the risk of Dermatite atopic.

Broadly the risk of allergic demonstrations increases according to the number of parents reached. The atopie is more frequent among boys than in the girls.

Clinical demonstrations

Allergy to proteins of the cow's milk

The APLV (Allergy to Cow's milk Protein) dominates the table of the allergy to food during the first months of the life.

The acute table is easy to recognize. It appears by a vomiting occurring in the hours following the catch of the feeding-bottle. It can join an emission liquid saddles and be supplemented by the symptoms of a state of shock with Collapsus, simple paleness with Cyanose péribuccale or Hypotonie with disorders of the conscience. The symptoms disappear in a few hours. Another feeding-bottle starts the same disorders.

The chronic digestive form of the APLV associates a syndrome of malabsorption with stéatorrhée which is constituted in a few weeks after the introduction of the PLV: break of the curve of weight, Anorexia, abdominal Météorisme contrasting with a Denutrition visible with the level of the members.

Age of occurred

The PLV are the only food antigens (cf Définition Antigène) of the first months of the life and can start reactions of allergy in a way early, even very early, as of the first hours. The symptoms appear in 10% of the cases in the two hours following the ingestion of the first feeding-bottle, in 30% of the cases in the first twenty-four hours and 75% to 100% of the cases before the 3 months age.

Allergy to other food

Although the APLV is a food allergy which is the subject of many medical publications, there exist other food presenting of the allergic risks of reactions. Thus, the fruits, the dry vegetables (soya, beans), eggs, shellfish (crab, shrimps, lobster, lobster), fish, vegetables, seeds of sesame, seeds of sunflower, mustard seeds and seeds of poppy can be the cause of an allergic reaction of a food nature.

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