An allergic reaction is a pathological response of the body's defense system to the influence of an irritant – allergen. Ultimately, the body begins to synthesize antibodies that are designed to resist allergens, but are perceived by them as hostile.
Thus, antibodies lead not only to the neutralization of the allergen, but also to damage to healthy tissues, provoke various types of allergic reactions. Most often, allergies occur in one form or another of skin dermatosis. What is the cause of skin allergic reactions, what are the methods for detecting allergies, will answer estet-portal.com.
Types of allergic reactions: etiological and provoking factors
The etiological factors that cause the development of various types of allergic reactions are currently not well understood. They are triggered by the earlier sensitization of the body by an allergen (one or more). An allergen is a substance to which the defense system responds with an atypical reaction. Allergens can be any antigens that the body regards as foreign.
All allergens are conditionally divided into 2 groups:
1. Infectious:
• bacteria particles;
• mushroom components;
• components of viruses;
• helminth particles.
2. Noninfectious:
• plant pollen;
• dust (street, book, home);
• detergents and cosmetics (powders, soaps, perfumes, oils, gels, shampoos);
• food products (milk, seafood, chocolate, fish, citrus fruits, honey, nuts);
• wool, skin particles, saliva of animals (mainly cats and dogs);
• chemicals (varnishes, paints, resins, solvents);
• poisons of animal origin (stings of bees, bumblebees, wasps);
• drugs (mainly antibiotics);
• latex (disposable gloves, condoms);
• ultraviolet rays;
• cold;
• synthetic clothing.
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Factors provoking various types of allergic reactions
In order to trigger manifestations of an allergic reaction, in addition to exposure to an allergen, one or more provoking factors must occur that significantly increase the risk of an allergy.
The occurrence of an allergic reaction is directly related to the individual susceptibility of the body. The effect of one allergen on the body of different people is different.
So, for example, one person consumes seafood without consequences, while in another they lead to the development of some type of allergic reaction.
Factors causing allergies:
• genetic predisposition;
• weakening of the body's defenses;
• formula feeding;
• diseases of the digestive tract;
• chronic diseases;
• hypersensitivity of the skin;
• viral and infectious diseases of the upper respiratory tract;
• presence of helminths or parasites in the body;
• pollution of residential premises (dust, non-compliance with sanitary standards);
• disturbed ecology;
• excessive use of cleaning chemicals;
• frequent consumption of potentially allergenic foods;
• violation of the rules and terms of vaccination.
violation of the rules and terms of vaccination.
Types of allergic reactions: classification
There are 4 types of allergic reactions:•
First type
This is an immediate reaction that proceeds according to the anaphylactic type (Quincke's edema, anaphylactic shock, bronchial asthma, allergic rhinitis or urticaria). After exposure to an allergen, the body's response in the form of an allergy is formed after a few minutes – a few hours.
•
Second type
It proceeds as a cytotoxic reaction, it is based on cytolysis (destruction) of cells. It develops more slowly, and lasts longer (up to several hours). Manifested by thrombocytopenia, hemolytic anemia, toxic allergy.
•
The third type
It is called the Arthus phenomenon and proceeds according to the type of immunocomplex reaction. It is based on the formation of complexes of antibodies and allergens (antigens), which are deposited on the walls of capillaries and destroy them. This reaction continues for several days. Manifested by allergic conjunctivitis, glomerulonephritis, systemic lupus erythematosus, hemorrhagic vasculitis.
•
Fourth type
It proceeds according to a delayed type of allergic reaction or late hypersensitization. Develops within at least 24 hours. Manifested by contact dermatitis, rhinitis, asthma. Read also:
Urticaria after stress: mechanism of development and treatment methods
Types of allergic reactions: skin manifestations
The main manifestations of allergic skin reactions include:
•
– manifested by dryness, itching and irritation of the skin;
•
– accompanied by hyperemia, swelling, itching of the skin area in contact with the allergen, the appearance of rashes in the form of papules and vesicles;
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– similar to a nettle burn and is accompanied by the appearance of hyperemic spots raised above the surface of the skin, with a tendency to merge, intense itching, weakness, dizziness;
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– manifested by multiple rash in the form of vesicles with serous contents, prone to open and form erosion, and subsequently scabs, scars;
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– accompanied by a profuse pink or red rash that later leads to blistering;
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– manifested by night itching, rashes in the form of hyperemic spots, which later merge into plaques, swelling of the skin;
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– accompanied by swelling of the mucous membranes, swelling of the subcutaneous fatty tissue (more often manifested on the face), hoarseness, shortness of breath, cough;
What symptoms of Quincke's edema require immediate intervention
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– refers to severe drug allergy, manifested by the appearance of vesicles, which, opening up, form cracks, erosions, ulcers on the skin;
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Steven-Johnson Syndrome
Methods for identifying types of allergic reactions
Various tests and tests are performed to confirm the diagnosis and identify a specific irritant
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Blood tests
When an allergy develops in the peripheral blood, an increased level of eosinophils, class E immunoglobulins is detected.
•
Skin tests
Various allergens are injected into the patient intradermally, their number can be up to 20 varieties. Each allergen is applied to a specific skin area. A positive reaction manifests itself for half an hour in the form of redness, itching and swelling. The more intense the manifestations, the stronger the effect of the allergen for this patient.
Antihistamines should be discontinued 48 hours prior to skin testing as they may cause false test results.
•
Skin tests
Appliques of paraffin, petroleum jelly and a number of allergens (chromium, benzocaine, drugs) are applied to the skin. Applications must be kept on the skin for 24 hours. They are used in the diagnosis of contact dermatitis, eczema.•
Provocation tests
It is 100% reliable in establishing the cause of an allergy, but the most dangerous method of examination. Provocative tests are performed in a hospital under the supervision of a group of doctors. The suspected allergen is injected into the digestive tract, nasopharynx, sublingually.
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