Causes of respiratory allergies

In respiratory allergies, inhalation sensitization to various exogenous allergens occurs predominantly.

Household allergens occupy a leading place in the formation of respiratory allergies.

House dust is multicomponent in composition. It includes allergens of house dust mites, epidermal, fungal, bacterial, chemical allergens.

A child with respiratory allergy may have hypersensitivity to both the complex allergen house dust and its individual components.

The main part of house dust consists of allergens of insect fauna of the house: chitinous shell, secretions and excrements of house dust mites (D. pteronyssimus, D. farinae, D. microceras, Euroglyphus mainae), cockroaches (Blattella germanica, Blattella orintalis). Many mites are found in carpets, upholstery fabrics, bedding, soft toys and furniture. The best conditions for reproduction of mites are a temperature of 22-26 °C and a relative humidity of more than 55%.

Tick sensitization in patients with respiratory allergies is characterized by year-round exacerbations with an increase in frequency in the spring-autumn period, with a worsening at night. In case of allergy to cockroaches, exacerbations often occur during the day.

The main sources of epidermal allergy are wool, fluff, feathers, dandruff, excrement, saliva of various animals (cats, dogs, guinea pigs, hamsters and other rodents, rabbits, horses, sheep, etc.). The most aggressive allergen of cat fur is feb 1; dog - Cad 2, found in saliva. High levels of these allergens remain in the house for several years after the animal is removed.

Exacerbations due to sensitization to epidermal allergens occur year-round, with an increase in the cold season, when the patient spends more time indoors.

Pollen allergens.

The high frequency of fungal sensitization in allergic diseases of the respiratory tract is explained by the widespread occurrence of mold fungi in nature. Their spores are smaller in size than pollen and are carried over long distances. The concentration of fungal aeroallergens is especially high in regions with high humidity.

External sources of fungal allergens include haystacks, fallen leaves, greenhouses, poultry and livestock farms, microbiological, pharmaceutical and food industries.

In the development of fungal sensitization in children, unsatisfactory living conditions are of great importance: mold on the walls in apartments with leaking roofs, stagnant water in basements. High concentrations of mold fungi are also noted in dust, in the soil of pots with indoor plants, in air conditioners and humidifiers, in cages with domestic birds and animals.

In case of sensitization to fungi of the genus Alternaria and Cladosporium, exacerbations become more frequent during the period of spore formation - from March until the first frosts. Fungi of the genus Aspergillus and Mucor are very common in damp rooms, where conditions are created for abundant formation of spores, which leads to year-round exacerbations.

Some groups of drugs can induce an exacerbation of allergic diseases of the respiratory tract. Among them, the leading place is occupied by antibiotics of the penicillin series (less often macrolides), sulfonamides, vitamins, aspirin and other non-steroidal anti-inflammatory drugs. An exacerbation of the disease can be associated not only with the use of these drugs, but also with environmental pollution by pharmaceutical enterprises.

Food allergens play a lesser role in the etiology of respiratory allergies than inhalation allergens, but their role in the formation and course of both minor forms of allergies (allergic rhinitis, recurrent laryngitis) and bronchial asthma, exogenous allergic alveolitis is well known.

Allergic diseases of the respiratory tract are characterized by age-related evolution of the sensitization spectrum: food allergy in young children, inhalation household allergy at 3-5 years, and pollen sensitization is added to school age. However, household sensitization also occurs in children under one year old, which is an unfavorable prognostic sign for the development of bronchial asthma.

Pathogenesis of respiratory allergies. Along with mucosal edema and hypersecretion, stimulation of afferent nerve endings by biologically active mediators causes sneezing and coughing. The acute phase of the atopic reaction lasts 30-40 minutes. The delayed reaction (late phase reaction) leads to infiltration of the upper respiratory tract mucosa by cells, which leads to the development of allergic inflammation in the mucosa, which is currently considered the main pathogenetic mechanism for the development of both minor forms of respiratory allergosis and bronchial asthma. Chronic allergic inflammation contributes to the formation of hyperreactivity of the respiratory tract. Hyperreactivity of the upper respiratory tract mucosa is clinically manifested by sneezing, rhinorrhea, nasal congestion, coughing in response to non-antigenic factors (cold air, physical activity, strong odors, etc.).

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