Allergic rhinitis: causes and pathogenesis

Causes of allergic rhinitis

The starting factors of the development of allergic rhinitis are mainly air allergens. The most common "home" allergens: secretions of house dust mites, saliva and animal dander, insects and allergens of plant origin. The main "external" allergens include pollen from plants and molds.

There is also a professional allergic rhinitis, which is most often accompanied by a lesion of the lower respiratory tract and is in the competence of occupational physicians.

In addition to air allergens, the cause of the disease can be the use of acetylsalicylic acid and other non-steroidal anti-inflammatory drugs. In this case, rhinitis is considered as a component of the "aspirin triad".

The role of heredity in the development of atopic allergy is universally recognized. This has been proven by genealogical data, observations of twins, statistical studies among populations of different countries, and by immunogenetic and molecular cytogenetic methods.

Pathogenesis of allergic rhinitis

Allergens, getting together with air in the nasal cavity, partially settle on the ciliated epithelium and, entering into local contact, sensitizes the body. When they re-enter the sensitized mucosa, an IgE-dependent allergic reaction is involved. Allergic rhinitis is characterized by inflammatory infiltration of the mucous membrane of the nasal cavity by various cells.

In patients with persistent allergic rhinitis, the degree of contact with allergens varies throughout the year, at certain periods it is very low. However, it is proved that even in the absence of symptoms, these patients have inflammation of the nasal mucosa: the so-called "minimal persistent inflammation". Manifestations of persistent rhinitis are considered the result of a complex interaction of allergy triggers and an ongoing inflammatory response.

Nonspecific nasal hyperreactivity is one of the main features of allergic rhinitis. An increased response to irritants of a non-allergic nature, which cause sneezing, nasal congestion and (or) rhinorrhea is characteristic. Against this background, the action of allergens on the nasal mucosa causes more pronounced clinical manifestations of rhinitis. Nasal hyperreactivity is considered a significant factor, the presence of which should always be considered in the diagnosis and treatment of allergic rhinitis. The study of the mechanisms of the development of the disease provides the basis for rational treatment, which presupposes an impact on a complex inflammatory response, and not only on the symptoms of allergy.

Interrelation with bronchial asthma

Studies confirm the presence of a direct link between allergic rhinitis and bronchial asthma: allergic inflammation of the nasal and bronchial mucosa plays a major role in the pathogenesis of these diseases. In this case, the same cells and mediators participate in the formation of the inflammatory focus in the mucosa and nose and bronchi. A provocative bronchial test with a specific allergen in patients with allergic rhinitis leads to an asthmatic response involving cells and proinflammatory mediators in the nasal mucosa, while provocative tests on the mucous membrane of the nose and in turn cause inflammation in the bronchi.

These facts support the concept of "single airways", which demonstrates a close relationship between allergic rhinitis and bronchial asthma and proves that the inflammatory response can be maintained and strengthened through interrelated mechanisms.

In this regard, patients with persistent allergic rhinitis should be examined for the presence of bronchial asthma. In turn, patients with bronchial asthma need to pay attention to the diagnosis of allergic rhinitis. Treatment should be aimed at eliminating the pathology of both the upper and lower respiratory tract.

[1], [2], [3], [4], [5], [6], [7], [8], [9], [10]