Allergies in children

Allergy in children develops by the same mechanism as in adults, and the causes of its occurrence are the same.

The beginning of the twentieth century was full of discoveries in various fields of science and technology. Medicine is not left out. Once, the Austrian pediatrician conducted a unique observation, which showed that the same substances give a violent reaction in most people. So there was a whole group called "allergens" and the term denoting the very reaction of the body to the action of allergens - an allergy. The name of the pediatrician who gave the beginning to the whole medical direction - allergology, - Kliment Von Pirket.

[1], [2], [3]

What causes allergies in children?

The opinions of scientists, up to the present time, have strong differences on the issues related to the true causes of allergies in general and in children in particular. There are several mechanisms for the development of allergic reactions, which are associated with disorders in individual body systems. They include:

• immune disorders;
• imbalance of intestinal microflora;
• increased number of allergens in the contact zone.

Allergy in children is often associated with all three causes, starting to act consistently, or, in other words, one reason becomes a platform for joining another. So, imbalance of intestinal microflora leads to the development of dysbiosis, and he, in turn, strikes the immune system. The immune system, weakened, is unable to cope with the receipt from the environment of harmful allergens of a chemical or biological nature. The child is surrounded by domestic animals, harsh flavors, including parfumery of parents, which can also become that very root cause. The constant exposure to an undetected allergen leads to agonizing manifestations. The intestine does not cope with food allergens, and the medicinal allergens destroy the already weak intestinal flora.

Thus, we get a vicious circle, which can be broken only by careful detection of the allergen and a phased selection of the right therapeutic methods.

Allergic disorders of varying severity (from skin reactions to anaphylactic shock) and localization (atopic dermatitis, conjunctivitis, rhinitis, bronchial asthma, etc.) develop due to contact with exogenous allergens - genetically alien substances. When they first enter the body, they cause the development of sensitization (more often with the hyperproduction of specific IgE antibodies fixed on mast cells). The bulk of allergens are proteins (as a rule, the molecular weight of allergens is 10,000 - 20,000), but they can also be hapten - low-molecular substances that become immunogenic only after the complex is formed with tissue or plasma carrier proteins.

The main groups of exogenous allergens

1. Aeroallergens - are in the air in a significant amount of allergens:
   • pollen allergens (trees, grasses, weeds);
   • allergens of home dust (a complex of home dust allergens, house dust mite allergens, cockroach allergens);
   • allergens of fungi (out-of-home, intramuscular);
   • epithelium and other animal allergens.
2. Food allergens.
3. Medicinal allergens.
4. Allergens of venom stinging insects.
5. Industrial chemical and biological substances.

A more detailed description of allergens is given in the sections of individual nosological forms of allergic diseases.

The classification of R. Jell and P. Coombs (RRA Gell and P G. N. Coombs) implies the division of allergic reactions into 4 types. It should be emphasized that such a division into types of allergy is based on the prevailing form of the immune response. In reality there is a close relationship between them and often a combination.

The German school of immunology offers a V type allergy selection, in which antibodies to cellular receptors (eg, to hormones) exert stimulating or blocking effects on the function of these target cells. They also suggested separately to consider type VI (or IIa), in which cytolysis performed with the participation of specific antibodies (not activating complement), is mediated through FcR of non-specific killer cells. This is the so-called AZPC - antibody-dependent cellular cytotoxicity, by which the organism is released from virus-infected cells and bacterial agents that do not die inside the phagocytes (eg, Gram-negative cocci).

Pathogenesis of allergies in children

The allergic process consistently goes through the stages:

1. Immunological: the interaction of the antigen with homocytotrophic antibodies of classes IgE or IgG4, fixed on a mast cell (type I - hypersensitivity reactions of immediate type); specific site of the antibody with the antigen of the target cell membrane (type II - cytotoxic damage); Nonspecific fixation of the CEC on a cell with FcR and C3R (type III - diseases of immune complexes, vasculitis) or specific T-cell receptor of the killer cell with the target cell antigen (IV t and n - delayed-type hypersensitivity - HRT). Thus, cell involvement is a common feature of the allergic form of the immune response:
2. pathochemical - liberation and synthesis of chemical mediators of allergy;
3. pathophysiological - clinical manifestations.

The "early phase" of anaphylaxis. In the pathochemical stage, the stage of liberation and formation of primary mediators and secondary ones is singled out.

The key mechanism of local and general manifestations of Type I allergy is the degranulation of mast cells with the release of preformed primary mediators transported and synthesized by this cell. Among the mediators, histamine, the platelet-activating factor (FAT), the eosinophil chemotaxis factor (FHE), prostaglandin D are released first in time (already at the 3 rd minute).

Further within half an hour, leukotrienes (slow reacting substance of anaphylaxis - MRS-A), thromboxane A2, endoperoxides, as well as active forms of kinins activating the blood coagulation factor XII, ie coagulation cascade, are secreted. At the same time, a whole range of enzymes, as well as cytokines, are released from the mast cells. This is the so-called "early phase" of anaphylaxis.

The "late phase" occurs 6-12 hours (only at high antigen concentrations) and has a pronounced inflammatory component mediated by the mediators of activated eosinophils, polymorphonuclear granulocytes, platelets and macrophages. In this phase, there is an increase in vascular permeability, migration of leukocytes along the surface of the endothelium (the "rolling effect") due to their interaction with adhesion molecules, fixation of cells on the vascular endothelium at the site of the reaction, and migration of cells into tissues. On the skin, in this case, erythematous infiltrates are formed, in the lungs - obstruction caused by changes in the bronchial mucosa.

The trigger moment of inflammation in allergy II (antibody-mediated cytotoxic) and type III (immunocomplex-mediated, Arthus type, "immune complex diseases") - activation of the complement system. The components of the complement system activated in these cases along the classical pathway have a spectrum of effects: chemotactic, anaphylatoxic C3d, Cla (non-specific mast cell degranulation), oponizing C1b, activating the release of granules with neutrophils - C5a, cytolytic - membrane membrane complex - C6, C7, C9. Morphological characteristics of complement deposits for II, III types are different.

Primary mediators of type IV allergies - lymphokines (cytokines) are isolated from specific T-lymphocytes and have the following effects: chemotactic, blast-transforming, and cytolytic and regulatory.

Secondary mediators of allergies of all types of allergic reactions are common. As mentioned above, these are mediators of inflammation, hemostasis, hematopoiesis: biologically active substances of blood leukocytes, platelets, endotheliocytes; cascade-activated proteolytic plasma systems (clotting system, plasminic, kinin, complement), arachidonic acid metabolites, reactive oxygen species, NO, pro-inflammatory cytokines, chemoattractants, growth factors, neuropeptides (of substance type P). It must be remembered that in the process of activation of cascade plasma systems new biologically active substances C3a, C5a-anaphylatoxins are formed, which cause direct degranulation of the mast cell; bradykinin - a vasoactive peptide, active proteases that increase the permeability of the vascular wall, and many others.

Clinical manifestations of allergic diseases are an integrative result of the action of primary and secondary mediators with the predominance of individual groups of substances, depending on the type of allergy. In the regulation of allergic inflammation, the neuroendocrine system participates through a system of transmitters, neuropeptides, and tissue hormones. Homeostatic control is carried out with the participation of adrenergic, cholinergic and non-adrenergic-non-cholinergic nervous system.

Allergens that cause IgE-mediated allergic reactions are thymus-dependent, that is, require the mandatory involvement of T-helpers to induce an immune response. In this case, type II helper (Th2) via IL4 stimulates B-lymphocytes to synthesize specific IgE antibodies; through IL-3 provide maturation and involvement in inflammation of mast cells; through IL-4, -5 - eosinophils, and through the colony-stimulating factor - macrophages. Thus, type II helper T cells, mast cells and eosinophils using cytokines (IL-4, -5, -13) and membrane-bound molecules (gr39), with the participation of IgE antibodies, create a network of mutually directed positive signals (vicious circle) supporting the allergic inflammation (type I allergies).

What is an allergen?

A list of substances that can cause allergic reactions from the body, a great many. For simplicity of definition, study and elimination, it is conventionally allocated allergens by their nature, which can be:

• food;
• chemical;
• drug;
• biological.

The most common are dust allergens, including small pincers, in large quantities contained in layers of house dust, plant pollen, microorganisms and substances contained in the wool of pets, food. In the past few years, multiple cases have been identified, when the allergy in children developed in response to the effects of mold fungi. The areas of mold, which are formed in domestic conditions in rooms with high humidity, on foodstuffs, become one of the strongest allergens.

An allergen can be served by absolutely any substance, drug or food component, which at first glance seems completely harmless. Typically, the symptoms appear instantly after interacting with the cause of the allergy.

Species classification of allergy

From the classification of allergens into groups, depending on the nature of their origin, the classification of allergy types also originates. Consider the most common types of allergies, among which:

• food;
• seasonal;
• cold;
• atopic dermatitis.

Food allergies in children

Allergies in children, especially infants, are directly related to the food that enters their body and the food that the mother takes. During the errors in the diet, which allows lactating women, the child has frequent rashes on the cheeks, intertrigo and redness in all large folds of the body: inguinal, popliteal, elbow, cervical, axillary. Quickly join problems with the intestines. Frequent diarrhea, which is watery in nature, pain in the abdomen, accompanied by the constant crying of the child and pulling the knees to the chest. If the necessary measures are taken, the redness on the cheeks can develop into small sores, which, merging, form a continuous crust, with the stretching of the skin, on which small cracks appear, delivering strong pain to the child. Fatigue severely "eat away" the skin, also leading to the formation of open ulcers. All this is a reaction to a food allergen.

If the baby's diet is completely made up of mother's milk and, in this case, the first signs of an allergic reaction appear, an analysis should immediately be made of the products that make up the diet of the mother's diet. It is best to exclude, for a short time, absolutely everything that at least somehow can relate to the number of allergens. To make a diet so that its basis was made up of cereals, chicken fat-free broths, cottage cheese, compotes from dried fruits, vegetable oils (sunflower, olive, soybean). Drink better, only clean water. When switching to such a strict diet, the allergy in children should pass in the first day. If the symptoms persist, it should be assumed that there is a reaction to the milk protein, which is the main component of any milk. In this case, as soon as possible, ask for help from a pediatrician or an allergist.

From milk mixtures, allergies happen more often than from mother's milk. When switching from one method of feeding to another, the allergy in children manifests itself quite often. This is due to the fact that the body receives a new protein. In cases of detection of allergy to some kind of mixture, one should not experiment and leave it in the child's diet, it is better to choose a formula of the other company's milk mix, and it is necessary to pay attention to the components that make up it. It is very likely that the composition will show a vitamin supplement, which is the same as allergens. In any case, as soon as an allergic reaction to food has manifested, the pediatrician should be consulted in order to jointly choose the most optimal variant for eliminating the causes and all the undesirable consequences associated with it.

[4], [5], [6]

Seasonal allergies in children

When one season changes to another, many adults begin to experience allergic reactions to certain irritants. Seasonal allergies in children occur not only in spring, when the time of flowering begins, it may appear in the summer, when the first pollen is formed, in the autumn, when the late grasses bloom and even in winter - the organism can respond to very low temperatures by allergic manifestations. Allergies in children can also refer to the number of seasonal manifestations. Therefore, attention should be paid to the appearance of such symptoms as reddening of the eyes and increased lacrimation, a persistent runny nose, swelling of the mucous membranes, especially the larynx, reddening of the skin with a profuse rash on them. If these symptoms appear from time to time, with relapses at certain times of the year, you can safely assume that these are signs of seasonal allergies.

Seasonal allergies in children, which is manifested in the spring to autumn, is also called "hay fever" due to its connection with the beginning of flowering of many herbs that later go to harvest hay.

Cold Allergy to Children

Cold allergy in children begins just like any other kind: reddening of skin with severe itching, the appearance of rashes and swelling in certain areas of skin. In the future, a spasm of the airways joins. As soon as the child falls under the influence of low temperatures, breathing immediately becomes difficult. This is a clear sign of an allergy to cold. It is very difficult to determine the exact diagnosis on your own and to isolate the original cause at home. Bronchospasm can cause not only allergic manifestations at low temperatures, but also be a sign of the onset of an acute inflammatory process. Calling a doctor and constantly monitoring the changes in symptoms to the measures applied, this is what needs to be done at the very first time.

[7]

Atopic dermatitis

Often you can see, especially on products intended for children, but with packaging designed for adults, a photo of a baby doll with bright red cheeks. The color of the cheeks on the photo is so bright that it causes many adults to be touched and accepted as a sign of good health of the baby. However, any medical specialist will say that such a hyperaemia of the cheeks is by no means a sign of good health, but a symptom of a skin allergic reaction. Allergy in children, which manifests itself repeatedly and passes into a chronic stage, is called atopic dermatitis. It is his manifestation of red cheeks in children, when they are closely examined, one can see that redness is not the only thing on the cheeks, they are completely covered with a rash.

Atopic dermatitis is called differently, often diagnosed as "diathesis", but it is more generalized name for a number of allergic diseases, the main manifestation of which is a skin reaction. Allergies in children, proceeding on the principle of atopic dermatitis, develops from infancy and can occur up to the youthful period. There are four stages of atopic dermatitis, which follow one after another in stages:

• infant (from 0 to 2 years);
• children's (up to 13 years);
• teenage (13-15 years);
• adult (15-18 years).

Each of these stages has its own differences and the mechanism of percolation. The fact that these stages occur step by step, following one after another, does not mean at all that it is impossible to cure atopic dermatitis, at each stage. The child's organism can "outgrow" this disease at any stage, and it will cease to be renewed. To do this, it is necessary to take medical and preventive measures on time and observe a strict diet and adhere to all the rules of personal hygiene, do not deviate from all the recommendations of a pediatrician and an allergist.

[8], [9], [10]

Diathesis

Allergy in children, manifested in skin reactions, in everyday life, most often, is called one word "diathesis". In fact, diathesis is just a form of allergy, a certain predisposition of the child's organism to respond to allergens. Diathesis is not only a rash on the skin and its redness, it's also an intertrigo that occurs constantly, and seborrhea areas on the scalp, and a host of other symptoms. Diathesis, only, plays the role of a harbinger of the possible development of many diseases, for example:

• exemplar;
• dermatitis of different etiology;
• neurodermatitis;
• psoriasis.

Diathesis has the nutritional nature of origin, is more often associated with impairments in the mother's diet than in the inaccuracies of the baby's own diet. Abuse of certain types of foods during pregnancy can with a high degree of probability guarantee the appearance, after birth, in a child of diathesis. The category of products of diathesis risk include eggs, nuts, honey and oranges. During pregnancy, you need to be more careful in taking these products.

[11], [12], [13], [14], [15], [16]

Allergy in children: diagnosis

Allergy in children is, unfortunately, quite common. In recent years, an increasing number of children suffer from such a disease. This is due to environmental errors in the environment and, as it is not a regrettable low level of health indicators of future parents.

To diagnose, based on symptoms, approximate reasons for their appearance and the nature of their course, is quite simple. To establish the predisposition to certain allergens it is necessary to make special analyzes, the adequacy and necessity of which, the allergist doctor will indicate. To begin to struggle with an allergy it is necessary without fail with visiting of this doctor. Only he is able to assign the correct list of all the necessary tests. It often happens that parents make their own choice in favor of certain allergic tests, many of which are absolutely unnecessary for the child and are not indicative, due to insufficient age or do not reflect the essence of this cause.

[17], [18], [19], [20]

Treatment of allergies in children

The allergist doctor prescribes carrying out all necessary allergological tests, analyzes and, on the basis of the data obtained, selects the most appropriate treatment. Most often it consists of such areas as:

• Blockade of release of mediators from mast cells (membrane stabilization).
• Blockade of synthesis of biologically active substances, active radicals O2, cytokines, NO; inhibition of Ca intake into the cell and its accumulation in the cytoplasm due to an increase in the synthesis of cAMP.
• Blockade of H1-histamine receptors.
• Effects on the functional activity of biogenic amine antagonists.
• Increase the removal of allergens from the intestine and through the kidneys.
• Specific immunotherapy (obsolete names: hyposensitization, desensitization).
• Maximum exclusion of allergen on the child's body;
• Admission of antihistamine drugs that relieve the symptoms of the allergy itself;
• Selection of a diet and strict observance of it;
• Removal of concomitant symptoms and treatment of secondary diseases;
• General strengthening procedures and measures.

It must always be remembered that an allergy in children is the protection of the body from elements that are alien to it. An allergic reaction, a weak child's body signals that substances have entered into it that he can not cope with. Attentive parents pay attention to all the unexpectedly appeared red spots, rashes and irritations, start to sound the alarm and quite right. The earlier the cause of allergic reactions is eliminated, the faster the organism of the child will restore the disturbed functions.

Allergies in children should be perceived, first of all, not as a dangerous disease, but as an aid to the child's organism, which it provides to surrounding adults in the search for and elimination of harmful causes for it.