ALLERGIC DISEASES of ORAL MUCOSA Allergy Is the Perverted
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ALLERGIC DISEASES OF ORAL MUCOSA Allergy is the perverted reaction of an organism to certain substances of the antigenic nature which in norm do not cause the painful phenomena. Endocrine and nervous systems, and also pathology of a gastroenteric tract play important role in allergy occurrence. Various substances can become the allergy reason: simple and difficult chemical compounds (iodine, bromine, proteins, polysaccharides) which getting into an organism, cause development of humoral and cellular immunologic reactions (an inflammation, a spastic stricture of bronchial muscles, a necrosis, a shock etc.). The substances causing development of allergic reactions are called allergens. The quantity of allergens in the nature is great enough, they are very various, both on structure, and on properties. According to origination the allergens are divided to exogenous and endogenous. Exogenous allergens get into an organism from the outside, and endogenous are originated in the organism and are own, but modified proteins. Thus, endogenous allergens are auto allergens. Exogenous allergens are: -Infectious - microbes, fungi, viruses, Chlamydia, protozoa -Non-infectious - vegetative, medicinal, alimentary, household, industrial etc. Endogenous allergens are: - Natural, or primary-some structures of an organism (a lens, a thyreoglobulin, etc.) which in norm do not cause the immune reaction of an organism - Acquired, or secondary - are formed in an organism during disturbances of metabolic processes under the influence of any pathological infectious or non- infectious factors (a cold, radiation, burns etc.). In a current of allergic reactions three stages are distinguished: 1) immunologic 2) biochemical (pathochemical) 3) pathophysiological The immunologic stage begins with organism and allergen contact, which result in organism sensibilization that is origination of the antibodies which are capable to co-operate with the given allergen. If after that allergen leaves from an organism no pathological reactions occur. Thus, the first penetration of allergen into an organism has sensitizing influence. In case of repeated entrance of allergen in already sensitizing organism allergen-antibody or allergen-sensitizing lymphocyte complex is formed. The stage of allergic reaction which is characterized by development or emission of biologically active substances - BAS, allergy mediators (Histamine, serotonin, etc.) begins with this moment and pathochemical. The pathophysiological stage of allergic reaction or stage of clinical features is a result of BAS influence on tissues and organism organs. It is a stage of clinical implication of an allergy: blood circulation disturbances, spasm of bronchial and intestinal muscles, changes of structure of blood serum, disturbance of coagulability of blood etc. are characteristic. Based on the development mechanism following allergic reactions are distinguished: 1) immediate type 2) cytotoxic 3) reactions of Artuse phenomenon type (immune complexes) 4) slowed down type (cellular hypersensitivity) Each of these types of allergic reaction has the special immune mechanisms, and the mediators that cause features of a clinical current of allergic diseases. 1) Allergic reactions of the first type are called also anaphylactic or atopic. They develop during interaction of an antigen with antibodies of type IgE and IgG which are called reagents. IgE and IgG are adsorbed on tissue basophiles and fat cells. Interaction of an antigen with reagents causes degranulation of the basophiles and fat cells. As a result, in intercellular space there is an emission of mediators of an allergy being inside these cells: Histamine, heparin, serotonin, prostaglandin (PG). Clinical features of an allergy of this type begin in 15-20 minutes after contact of an organism to allergen; therefore they are called reactions of immediate type. Anaphylactic shock, urticaria, bronchial asthma, hay fever etc concern to reactions of immediate type. 2) Allergic reactions of the second type (cytotoxic) - are characterized by formation of antibodies IgG and IgM, capable to activate a complement. In case of this type of reaction the antigen is a component of a cell or is adsorbed on it, and the antibody arrives in a tissue. Adhesion of antibody with an antigen causes complement activation, cell destruction, a phagocytosis and excision of the blasted cells and tissues. Medicinal allergies concern to reactions of cytotoxic type. 3) Allergic reactions of the third type (immune complexes) during which neither the antigen, nor an antibody are not a component of cells, and formation of an antigen-antibody immune complex occurs in blood and an intercellular liquid. In case of this type of reaction antibodies are IgG and IgM as well. Immune complexes settle down around vessels and in a vascular wall. It leads to disturbance of microcirculation and a secondary lesion of tissues, up to a necrosis. Autoallergic diseases concern to reactions of immune complexes (lupus erythematosus, etc.) 4). Allergic reactions of the fourth type (slowed down type) are characterized by T- lymphocytes co-operation with antigens. These T-lymphocytes have the receptors on the membrane capable to contact with antigen. When T-lymphocyte is joined to allergen, the mediator of cellular immunity - lymphokines is formed. About 30 various lymphokines are known by means of which T- lymphocytes become organizers of destruction of antigens by other leucocytes of blood. Lymphokines cause a clump of macrophages therefore the inflammation develops and the phagocytosis is carried out. Allergic reactions of the slowed down type develop in 24-48 hours after contact of allergen to an organism. Reactions of such type underlie almost all virus and bacteriemic infections (tuberculosis, syphilis etc.). Diagnosis: Diagnosis of allergic diseases is based on the allergological anamnesis, diagnostic and laboratory tests. During subjective examination (allergological anamnesis) the contacts with various household and industrial substances, predisposition of an organism to allergies, possible reasons of allergies should be taken into account. Diagnostic tests should be done in 2-3 weeks after acute implication of an allergy. Dermal tests are done: to find out a medicinal allergy - by means of application on a skin, allergy of a bacteriemic or fungal origination - an intradermal method. Reaction of basophiles degranulation (test of Sheili), and reaction of leukocytosis are concern to laboratory tests. Anaphylactic shock Anaphylactic shock (choc anaphylacticus) is the generalized anaphylactic reaction originating during interaction of the entered antigen with cytophilous antibodies. Anaphylactic shock is the highest step of implication of allergic reaction of immediate type. In dental practice anaphylactic shock can occur from anesthetics, analgesics, antibiotics, filling materials, including root channels sealers, impression materials etc. Clinical features: Anaphylactic shock develops suddenly, in some minutes, and even immediately after antigen introduction. The patient shows anxiety; has a feeling of fear, fever, and constraint in a breast. There are complicated breath, at first frequent, and then convulsive, nausea, vomiting, plentiful diaphoresis, hyperemia of integuments, headache, pulsation in head. Pupils extend and do not react to light. These symptoms are replaced by balance loss, falling, cramps. Spontaneous urination and defecation occur. Changes of cardiovascular system: tachycardia, threadlike pulse, sharp falling of arterial pressure- are characteristic for anaphylactic shock. Anaphylactic shock is not shown on oral mucosa. Differential diagnosis: The anaphylactic shock is necessary for differentiating from: - An acute heart insufficiency - A myocardial infarction (heart attack) - Epilepsies Treatment: The outcome of an anaphylactic shock depends on severity of symptoms less, than on complete and on time treatment. First of all it is necessary to stop allergen introduction in an organism. Horizontal position is given to the patient; prostheses should be removed from an oral cavity, and a mandible should be pushed forward and fixed in this position to prevent tongue asphyxia. 0,5ml of 0,1 % adrenaline solution or 2-4ml of 0,2 % epinephrine solution should be injected subcutaneously or intramuscularly (in serious cases intravenous introduction is prescribed) to increase arterial blood pressure. For bronchospasm cupping use 5-10ml of 2,4 % euphilinum solution intravenously. In case of cramps tranquilizers and neuroleptics (Seduxenum, Elenium) are used. Angioneurotic Quincke's edema Quincke's edema (oedema angioneuroticum Quinke) is promptly developing deep edema of the limited part of skin, connective tissue and mucosa which has a sudden onset; can spontaneously disappear and again be shown. For the first time this disease was described by German therapist Quinke. In case of angioneurotic edema the BAS deactivation and inhibition system is broken. It develops in case of hereditary deficiency of these inhibitors, disturbance of function of the organs deactivating BAS. Activation of BAS is very easily for these patients. This activation can be caused not only by a complex of antigen-antibody, but also by non-immune agents (for example, a cold). Under the influence of BAS there is an exit of an exudate and an edema of tissues. Clinical features: Disease begins sharply, within several minutes there is a limited expressed edema. The edema basically is localized in the field of lips, eyelids, external