Allergic reactions

Allergic reactions are a hypersensitivity of the body's immune system when it comes into contact with the stimulus. According to statistics, allergic reactions occur in about twenty percent of the world's population, with about half of the cases recorded in areas with poor ecology. 

The incidence of allergic reactions increases approximately two to three times every ten years. Far from the last role in this is the deterioration of the ecological situation, as well as stress. The most common factors that can provoke an allergic reaction include cosmetic and medicines, household chemicals, malnutrition, insect bites, dust, pollen, animal hair. Clinical manifestations of allergies can be localized in any part of the body, including the nose, lips, eyes, ears, etc. To detect the allergen, scarifying skin tests are performed with the introduction of an intradermally small amount of the suspected allergen. When medicinal treatment of allergic reactions completely avoid contact with the allergen.

[1], [2]

Causes of allergic reactions

The cause of an allergic reaction is an acute response from the immune system to irritants, leading to the release of histamines. Allergies can occur with direct contact of the allergen with the skin, with its inhalation, with food, etc. The most common allergens include animal hair, bee stings, fluff, dust, penicillin, food, cosmetics, medications, pollen, nicotine smoke , etc. The causes of allergic reactions include digestive disorders, inflammatory processes in the intestine, and the presence of worms. Any pathology of the gastrointestinal tract, liver and kidneys significantly increases the risk of allergic reactions. In young children, the cause of allergies can be the rejection of breastfeeding and the transition to artificial feeding. The causes of allergic reactions may be as follows:

• Unfavorable ecological situation.
• Frequent acute respiratory viral infections.
• Hereditary predisposition.
• Chronic obstructive pulmonary diseases.
• Hypersensitivity to the skin.
• Nasal polyps.

[3], [4]

The mechanism of an allergic reaction

A detailed mechanism for the development of an allergic reaction is as follows:

Primary contact with the allergen.

The formation of immunoglobulin E. At this stage, specific antibodies are accumulated and produced that combine only with the stimulus to which their formation is due.

Attachment of immunoglobulin E to the membrane of mast cells containing mediators of allergic reactions - histamines, serotonin, etc.

Acquisition by the body of a specific hypersensitivity to the allergen. During the period of sensitization (sensitization), the body accumulates immunoglobulins E, attached to the membrane of mast cells. Clinical manifestations of allergy in this period are absent, there is an accumulation of antibodies. The reactions of antibodies and antigens that cause allergies do not yet occur at this stage.

Secondary contact with the allergen and the formation of immune complexes on the membrane of mast cells. Allergen binds to antibodies and an allergic reaction occurs.

Release mediators of allergy from mast cells, tissue damage.

The effect of mediators on organs and tissues. At this stage, the blood vessels expand, their permeability increases, there is a spasm of smooth muscles, there is nervous stimulation, mucous secretion.

Clinical manifestations of allergy - skin rashes, itching, swelling, shortness of breath, tearing, etc.

In contrast to immediate type reactions, the delayed-type allergy is not due to antibodies, but to the increased sensitivity of T cells. In such cases, only those cells on which fixation of the immune complex of antigens and sensitized T-lymphocyte are destroyed.

Pathogenesis of allergic reactions

All kinds of allergic reactions are a consequence of the broken response of the body's immune system. The pathogenesis of allergic reactions consists of an acute and delayed period. If the body is hypersensitive to any substance, the secretion of immunoglobulin E instead of immunoglobulin M occurs in the first contact with the antigen or immunoglobulin G upon re-contacting. The increase in the sensitivity of the organism occurs during the binding of the immunoglobulin E secreted at the first contact with the crystallizing immunoglobulin fragments on the surface of mast cells and basophilic granulocytes. The next contact releases histamine and other mediators of inflammatory reactions and there are external signs of allergy. The period of delayed hypersensitivity comes after the weakening of the activity of the mediators of the inflammatory reaction and is due to the penetration of different types of leukocytes into its epicenter, which replace the affected tissues with connective. Typically, the delayed allergic reaction occurs four to six hours after an acute reaction and can persist for one to two days.

Stages of allergic reactions

The immune stage. It begins with the first contact of the immune system with the allergen and continues until the sensitivity begins.

The pathological stage. Occurs with a secondary contact of the immune system with the allergen, at this stage, a large number of bioactive substances are released.

Pathophysiological stage. At this stage, the functions of cells and tissues are violated, their destruction by bioactive substances occurs.

Clinical stage. It is a manifestation of the pathophysiological stage and its completion.

Manifestation of allergic reactions

The manifestation of allergic reactions can be observed from the cardiovascular, digestive and respiratory systems, as well as from the skin. The main manifestations of allergic reactions depending on the type of allergy are skin rashes, redness and painful tickling skin irritation, eczema, erythema, eczematids, edema and redness of the oral mucosa, abnormalities in the digestive system, such as abdominal pain, diarrhea, vomiting, nausea . The patient may get watery, a wheezing cough, a runny nose, wheezing in the chest, a headache, reddening of the eyelids. Manifestations of an allergy can be concentrated virtually on any part of the body, including the face, lips and eyes. Allergic manifestations are divided into respiratory, food and skin. Respiratory manifestations of allergic reactions affect various parts of the respiratory tract. These include allergic year-round and seasonal rhinitis (pollinosis), allergic tracheobronchitis, bronchial asthma. The main symptoms of allergic rhinitis are pruritus and nasal obstruction, frequent sneezing, discharge from the nose of a watery consistency, lacrimation, general deterioration of well-being. At a tracheobronchitis of an allergic nature there is a dry cough, more often at night. One of the most severe forms of respiratory allergic reactions is bronchial asthma, accompanied by attacks of suffocation. Manifestations of food allergies can be quite diverse. Often, it affects the skin, respiratory and gastrointestinal tract, eczema and neurodermatitis may occur. Most often, food allergic manifestations are localized on the bends of elbows and knees, on the neck, face and wrists. Skin allergic reactions are manifested in the form of urticaria, edema Quincke, atopic dermatitis. With hives, there is a rash and swelling of a certain area of the body, which, as a rule, does not cause itching and passes for a short time. Quincke's edema is an extremely dangerous form of allergy manifestation. In addition to skin rashes, soreness, puffiness and itching occur, and with a laryngeal edema, there is an attack of suffocation. When atopic dermatitis develops inflammation of the skin, which can be combined with rhinoconjunctivitis, bronchial asthma.

Local allergic reaction

Local allergic reaction can be manifested from the skin, gastrointestinal tract, mucous membranes, respiratory tract. Local allergic reaction to the skin is characterized by its dryness, hypersensitivity, itching, redness, rash, blistering. Cutaneous manifestations of allergies can change the place of localization, moving to different parts of the skin. An example of a local allergic reaction is atopic or contact dermatitis. Local allergic reaction may manifest from the gastrointestinal tract, as a rule, its symptoms are abdominal pain, nausea, diarrhea. With the localization of allergy symptoms in the eye area, the patient complains of lacrimation, swelling and redness of the eyelids, burning and painful tickling irritation in the eye. Such symptoms occur, for example, with allergic conjunctivitis. On the part of the respiratory system, signs of a local allergic reaction are rhinitis or nasal congestion, dry coughing, sneezing, wheezing in the chest, difficulty breathing (for example, with allergic rhinitis or bronchial asthma).

Allergic skin reaction

Allergic reaction to the skin, or allergic dermatitis, is characterized by a sharp inflammatory process on the surface of the skin and is divided into the following types:

Contact allergic dermatitis occurs only in persons who have specific to any substance immune cells-T-lymphocytes. The cause of such an allergy can be, for example, a completely harmless substance that does not cause a healthy person no symptoms. However, it should be noted that contact allergic dermatitis may occur when contacting with aggressive agents that are part of various medications, dyes, detergents, etc.

Toxico-allergic dermatitis is characterized by acute inflammation of the skin surface, sometimes - mucous membranes, developing under the influence of toxic-allergic factors, penetrating the body through the system of breathing or digestion, and also when injected into a vein, under the skin and into the muscle. Therefore, the effect on the skin is not direct, but hematogenous.

Atopic dermatitis (diffuse neurodermatitis). The main symptoms are itching and rashes on the skin, including the face, armpits, elbows and knees bends. This form of allergy can be the result of a genetic predisposition and have a recurring course. There are suggestions that in the development of atopic dermatitis, such factors as infectious pathologies, violation of hygiene standards, climate change, food allergens, dust, chronic stress play a role.

Fixed erythema is characterized by the formation of one or more round spots about two to three centimeters in size, which after a few days acquire a bluish tinge first, and then a brown one. In the middle of such a spot a blister can form. In addition to the skin surface, the fixed pigmentary erythema can affect the genitals and the mucous membrane of the oral cavity.

[5], [6], [7]

Allergic reactions in stomatology

Allergic reactions in dentistry can occur when a patient is injected with any medication. Clinical symptoms of such reactions may include swelling and development of the inflammatory process at the injection site, hyperemia and painful tickling of the skin, conjunctivitis, nasal discharge, urticaria, swelling in the lips, difficulty swallowing, coughing, and in the most severe cases anaphylactic shock , loss of consciousness, suffocation. To provide first aid to a patient in any dental office, preparations such as prednisolone, hydrocortisone, epinephrine, euphyllin, antihistamines should be available.

[8], [9], [10], [11], [12], [13], [14], [15], [16]

Allergic reaction to anesthesia

An allergic reaction to anesthesia, more precisely, to an anesthetic solution is relatively common, due to the presence of preservatives, antioxidants and other substances in addition to the anesthetics themselves. Clinical manifestations of an allergic reaction to anesthesia are divided into light, medium and heavy. With a mild allergy, itching and redness of the skin, a few days can be noted subfebrile temperature.

Allergy of moderate severity develops within a few hours and can pose a danger to the life of the patient. To severe reactions include the edema of Quincke, accompanied by an attack of asphyxia, as well as anaphylactic shock. Anaphylactic shock can develop within minutes after anesthesia, sometimes appears instantly and can occur even with the administration of small doses of anesthetic. After the introduction of an anesthetic, tingling, itching on the skin of the face, hands and feet, a feeling of anxiety, a decline in strength, a heaviness in the chest, pain behind the sternum and in the region of the heart, as well as in the abdomen and in the head. When a mild allergy to anesthesia is injected intramuscularly, antihistamine, for example, a 2% solution of suprastin. For allergies of moderate severity, the administration of antihistamines is combined with symptomatic treatment. With a sharp deterioration in the muscle or a vein injected glucocorticoids. The first aid for anaphylactic shock is the injection of an adrenaline hydrochloride solution (0.1%) into the anesthetic site.

[17], [18], [19], [20], [21], [22], [23]

Allergic reactions in pregnancy

Allergic reactions during pregnancy increase the risk of a similar reaction in the fetus. If a pregnant woman has an allergy, taking various medications can affect the blood supply of the fetus, so their choice should always be agreed with the attending physician in order to minimize the risk of adverse effects. For the prevention of food allergies, it is advisable to prescribe a hypoallergenic diet with the exception of foods that most often cause allergic reactions. Also recommended is the intake of vitamin-mineral complexes. Pregnant women should avoid inhalation of tobacco smoke, it is necessary to regularly ventilate the room and prevent the accumulation of dust, contact with animals should also be limited. Allergic reactions during pregnancy can occur against the background of hormonal changes in the body and, as a rule, take place at the period of twelve to fourteen weeks. A prerequisite for any allergic reactions is the exclusion of contact with the allergen.

[24], [25], [26], [27], [28], [29]

Allergic reactions in children

One of the most common allergic reactions in children is atopic dermatitis. It should be noted that an incorrect tactic of treating a disease can lead to the development of a chronic form. The main symptoms of allergic dermatitis include rashes on various parts of the body, accompanied by itching. The main reason for the occurrence of such conditions is a genetic predisposition. Among allergic factors that can provoke atopic dermatitis in infants and young children, there is a hypersensitivity to the protein of cow's milk and egg whites. In children of older age, atopic dermatitis can cause dust, animal hair, fungus, plant pollen, worms, synthetic clothing, temperature and humidity changes, hard water, stress and exercise, etc. In addition to itching and rash, reddening of the skin is noted, it becomes dry, thickens and flakes. Complications of atopic dermatitis can be a fungal attack on the skin and mucous surfaces.

[30], [31], [32], [33], [34], [35]

Allergic reaction to vaccination

An allergic reaction to the inoculation may manifest as urticaria, Quincke edema, Lyell syndrome, serum sickness, anaphylactic shock. In case of hypersensitivity to antibiotics or egg white, the risk of allergies to vaccination against CKD (measles, rubella, mumps) is high, with yeast intolerance - for injection against hepatitis B. Allergic reaction to vaccination in the form of urticaria is accompanied by itching and skin rashes, develops as a rule , from a few minutes to several hours after the injection. With Lyell's syndrome, a rash appears on the body, blisters, skin starts to itch.

Such a reaction can develop for three days after the introduction of the vaccine. In case of an allergic reaction to vaccination, one to two weeks after its administration, serum sickness may develop, combining the symptoms of urticaria and Quincke edema, accompanied by fever, increased lymph nodes, spleen, joint pain.

Serum sickness can have a negative impact on the functioning of the kidneys, lungs, gastrointestinal tract, nervous system. Anaphylactic shock in an allergic reaction to vaccination can occur rapidly or within three hours, and is along with Quincke's edema an extremely life-threatening condition, accompanied by a sharp drop in blood pressure and an asphyxia attack. In cases of such reactions, anti-shock therapy is provided.

[36], [37], [38], [39], [40], [41]

Allergic reaction to Mantoux

An allergic reaction to Mantoux can occur with allergies to tuberculin. In addition, the response to injection of tuberculin is one of the forms of allergic reactions, since it is, for the most part, an allergen, and not an antigen. But the process of interaction between tuberculin and the immune system remains completely unexplored. The Mantoux test parameters may be affected by food or drug allergies, allergic dermatitis, as well as any other types of allergic reactions. Also, the factors influencing the results of the test include the transferred infections of a different nature, chronic diseases, immunity to non-tuberculosis mycobacteria, the age of the patient. An allergic reaction to Mantoux can be the result of excessive sensitivity of the skin, an unbalanced diet in children, may occur during menstruation in female patients. Glaive invasion, adverse environmental factors, and disturbances in the storage conditions of tuberculin can also affect the results of the test.

[42], [43], [44], [45], [46], [47], [48], [49], [50], [51], [52]

Types of allergic reactions

1. Anaphylactic reactions (light, medium and heavy).

Localization of the lesion is skin, mucous membranes, upper respiratory tract, bronchi, gastrointestinal tract, cardiovascular system, central nervous system. With light anaphylactic reactions, tingling in the extremities is felt, itching, swelling of the eyelids, nasal mucosa, oral cavity, etc. Symptoms usually occur within two hours after contact with the allergen and persist for one or two days. The average anaphylactic reactions usually begin in the same way as the lungs and last one or two days. There may be bronchospasm, dyspnea, cough, urticaria, eczema, etc. Severe anaphylactic reactions are extremely life threatening condition, develop, as a rule, rapidly and begin with the symptoms characteristic of reactions of the lung type. Within minutes, there is a pronounced bronchospasm, the larynx and the mucosa of the digestive tract become swollen, breathing becomes difficult, the blood pressure drops sharply, the heart fails and the shock is abnormal. The more rapidly the anaphylactic reaction develops, the heavier it is.

2. Humoral cytotoxic reactions This type of reaction is carried out, like the first, by humoral antibodies. However, in cytotoxic reactions, the reactants are IgG and IgM. The second type of reactions include hemolytic type anemia, autoimmune thyroiditis, a decrease in granulocyte blood, caused by medication intake, a decrease in platelets,
3. Immunocomplex type of reactions

Immunocomplex reactions occur, as in the second type, with the participation of IgG and IgM. However, in this case, the antibodies interact with soluble antigens, rather than with those that are on the surface of the cells. Examples of such reactions are serum sickness, some forms of allergy to drugs and food, autoimmune diseases, glomerulonephritis, allergic alveolitis,

4. Slow-motion reactions

Examples of this type of reactions are contact dermatitis, tuberculosis, brucellosis, mycosis, etc. The cytotoxic T lymphocyte interacts with a specific antigen, releasing from the T cells the cytokines that mediate the symptoms of delayed hypersensitivity.

Toxico-allergic reaction

Acute toxic-allergic reaction may occur when a drug is introduced and manifested in the form of urticaria, erythema, necrosis of the epidermis with its further detachment from the dermis. The pathogenesis of a toxic-allergic reaction consists in the development of a nonspecific generalized vasculitis, which causes four degrees of severity of the disease. At the first and second degree of severity, the patient is treated in the allergology, therapy or dermatology department, at the third and fourth degree in the intensive care unit. Clinical manifestations in toxic-allergic reactions depending on the degree of severity may include increased body temperature, skin, mucous, liver and pancreas, urinary system, cardiovascular and central nervous system.

Allergic reactions of immediate type

Allergic reactions of the immediate type appear, as a rule, within twenty to thirty minutes after the second contact with the antigen and are associated with the production of antibodies. Allergic reactions of immediate type include anaphylaxis, atonic disease, serum sickness, acute necrotic hemorrhagic inflammation, IR diseases (immunocomplexes). Immune reaction to allergens, which in case of immediate type hypersensitivity can be dust, pollen of plants, food, medicinal, microbial, epidermal factors, leads to the production of antibodies (Am) of immunoglobulin E or G class and to increase the sensitivity of the organism. With secondary ingestion, the allergen combines with antibodies, which leads to cell damage and the further formation of a serous or other inflammatory process. Depending on the mechanisms of the lesion and the clinical picture, several types of allergic reaction of an immediate type are distinguished: mediator type (subdivided into anaphylactic and atopic), cytotoxic and immunocomplex.

[53], [54], [55], [56], [57], [58], [59], [60], [61], [62]

Allergic reactions of delayed type

Allergic reactions of a delayed type are caused by T-lymphocytes and lymphokines, caused by infectious agents, chemicals, including medications. The immune reaction is associated with the formation of T-lymphocyte effector cells that produce lymphokines that damage cells that contain antigens on their surface. Clinical forms of delayed-type hypersensitivity include tuberculin and trichophytosis infectious allergies, contact allergies, certain forms of drug allergy and autoimmune diseases. For diagnosis, skin tests and test tubes (cell type) are carried out.

[63], [64], [65], [66], [67], [68]

Allergic reaction by type of urticaria

Allergic reaction by the type of urticaria is characterized by the appearance of blisters on the skin and mucous membranes upon contact with the stimulus. The reasons for the occurrence of such reactions are quite diverse, which is why it is not always easy to establish an allergen. Acute allergic reaction by type of urticaria is usually associated with taking medications, food, with infections and a bite of insects. The chronic form of urticaria has a connection with pathologies of internal organs and disorders of the functioning of the nervous system. Physical urticaria can occur when exposed to the skin by direct sunlight, warm, cold, vibration and compression. In an allergic reaction to the type of urticaria, there are signs such as the formation of blisters on the skin or mucous membranes, characterized by swelling, compactness, various sizes and contours, often with a blanching zone in the middle. In acute allergic reaction by the type of urticaria, the onset of the disease, as a rule, is rapid, there is a strong painful tickling of the skin, burning, rashes in various places, nettle fever. To varieties of allergic reactions by the type of urticaria include giant urticaria (edema Quincke), chronic recurrent urticaria, solar urticaria. In acute form of the disease, resulting from the reception of any medicine or food, shows the intake of laxatives, antihistamines, as well as calcium chloride and calcium gluconate. In severe cases, corticosteroids and adrenaline solution are administered. For external treatment, use 1% menthol solution, salicylic acid solution or calendula. In cases where it is not possible to detect the allergen, the patient is shown absolute fasting from three to five days under strict observation by the doctor.

[69], [70], [71], [72], [73], [74]

Treatment of allergic reactions

Treatment of allergic reactions is primarily based on the complete limitation of the patient's contact with the irritant. When carrying out specific immunotherapy, the patient is administered a vaccine containing a specific antigen, gradually increasing the dosage. The result of such treatment can be both a reduction in the severity of the disease, and the complete elimination of hypersensitivity to the irritant. This method is based on stimulating the release of immunoglobulin G, which binds antigens before their connection with immunoglobulin E, thereby blocking the development of an allergic reaction. Drug medications belonging to the group of antihistamines, as well as adrenaline, cortisone, and euphyllin also have the ability to neutralize the activity of mediators of the inflammatory reaction. Such drugs help to remove allergy symptoms, but can not be used for long-term therapy. In the treatment of allergic reactions to food or drugs enterosorbents are used. Antihistamines used in the treatment of allergic reactions are divided into groups of the first, second and third generations. With each successive generation, the number and intensity of side effects and the likelihood of habituation decrease, the duration of the effect increases.

• Antihistamines of the 1st generation - fenistil, dimedrol, tavegil, diazolin, dramamine, diprazine, suprastin.
• Antihistamines of the second generation - allergodyl, klaritin, zodak, cetrin.
• Antihistamines of the third generation - lordestin, erius, telphast.

First aid for allergic reactions

First aid for allergic reactions consists primarily in the immediate cessation of contact with the allergen. If an allergy occurs on food, you should immediately wash the stomach. If more than sixty minutes have passed since taking food, you should take a laxative or put an enema. Suspend the penetration of allergens into the blood can be with activated charcoal or other sorbents. It should be noted that the simultaneous use of sorbents with other drugs prevents the absorption of the latter, so sorbents, along with other medications, do not take. If an allergic reaction has occurred on the bite of an insect, the stinger must first be removed. To remove puffiness on the affected area, ice should be applied for about thirty minutes, possibly also applying a tourniquet over the site of the bite. With allergies related to inhaling dust, pollen, wool, etc., you must immediately take a shower, wash your eyes and nasal passages in order to cleanse the skin and mucous membranes from allergen particles. To suppress the symptoms of allergies, you must take an antihistamine drug (claritin, suprastin, cetrine, loratidine, zodak, etc.).

[75], [76], [77], [78]

How to remove allergic reaction?

The main task in eliminating the symptoms of allergy is the complete elimination of contact with the stimulus. If the patient is difficult to breathe, in no case can self-medication be done, an ambulance should be called immediately. If an allergic reaction has occurred after an insect bite, such as a bee, you should try to pull the sting, then the affected area needs to be treated with soap and ice or another cold, such as a compress.

To reduce swelling on the damaged skin area, you can apply a thick mixture of soda and water. If the cause of the food allergy is food, to eliminate the allergen, firstly wash the stomach and put a cleansing enema. If you are allergic to cosmetics, you should immediately wash your skin with water. Hydrocortisone ointments help reduce the itching and irritation of the skin. To remove the allergic reaction, it is necessary to take an antihistamine drug, if there are no contraindications to its use (cetrine, claritin, zodak, suprastin, etc.).

Nutrition for allergic reactions

Nutrition for allergic reactions should be necessarily balanced and full. When allergies are not recommended to abuse sugar and sugar-containing products, you can use its substitutes. If you are addicted to allergies, you should monitor the intake of protein, fat and carbohydrates, it is recommended to reduce salt intake. Sharp and spicy dishes, seasonings, smoked products, fatty meat and fish should also be limited or completely eliminated. In the diet of dietary nutrition is recommended to include cottage cheese and dairy products. Food is recommended to cook for a couple, cook or bake, but do not fry. This to some extent helps to slow the absorption of allergens by the intestine. In addition to the basic diet prescribe the intake of vitamin-mineral complexes, as well as calcium preparations. At the same time, products containing oxalic acid, which slows the absorption of calcium, are excluded. Some fish species, such as, for example, tuna or herring, contain histamine, which increases the allergic reactions. With food allergy, an elimination diet is appointed, completely eliminating the consumption of the allergen product, for example, when egg yolk is allergic, it is forbidden to eat eggs and any products containing them in one form or another. 

Prevention of allergic reactions

Prevention of allergic reactions in the first place is to exclude contact with the allergen, if any. For preventive purposes, it is also possible to designate a specially designed dietary table that contains products balanced in terms of energy value and hypoallergenic content. To prevent the penetration of allergens into the body, as well as to prevent repeated allergic reactions, correction of nervous conditions is necessary, stressful situations should be avoided, more should be in the open air, abandon bad habits, and lead a healthy lifestyle. To prevent the development of allergic reactions, also recommends the holding of special respiratory gymnastics, strengthening the body with the help of hardening or physical education.