Nasal mucus analysis

In healthy individuals, smears obtained by scraping from the posterior section of the inferior nasal concha and stained according to Wright-Giemsa reveal cylindrical, ciliated cylindrical, goblet and basal cells, which are stained pale blue; eosinophils, basophils and mast cells are absent, the number of neutrophils and bacteria is insignificant; the content of goblet cells does not exceed 50% of the total number of epithelial cells.

In normal conditions and during banal inflammation, eosinophilic leukocytes are not absent in the nasal secretion, or the ratio of eosinophils to neutrophils is 1:10. The detection of a large number of eosinophils in the nasal secretion reflects the body's allergic reaction to the introduction of allergens into the upper respiratory tract. Local diagnostics of the allergic process is facilitated by the fact that the relative content of eosinophils in the tissues and on the surface of the mucous membrane of the upper respiratory tract in allergic diseases sharply exceeds their content in the peripheral blood. The study of nasal mucus is especially valuable for the diagnosis of allergic diseases of the nasal cavity and paranasal sinuses.

The number of eosinophils in nasal secretion increases with allergic processes in the mucous membrane of the upper respiratory tract, but to varying degrees depending on the type of allergen, type of allergic reaction, exacerbation or remission of an allergic disease. Therefore, in some cases, during an exacerbation of allergic rhinosinusitis, a large number of eosinophils are found in nasal smears, and in the interictal period only single eosinophils are detected; in other cases, there is no difference in the number of eosinophils in the secretion depending on the phase of the disease. The number of eosinophils in the secretion of the nasal cavity depends on the type of allergen and the routes of its penetration into the body. With inhalation allergy, pronounced eosinophilia is noted, and with food sensitization, the number of eosinophils is less. The study of nasal secretion plays an important role in the differential diagnosis of allergic and vasomotor rhinitis. Eosinophilia is characteristic of allergic rhinitis. The presence of eosinophilia in nasal secretions is an important diagnostic sign not only of allergic rhinitis, but also of respiratory allergies in general.

In recent years, great importance in the diagnosis of allergic diseases is attached to the detection of mast cells in the nasal secretion. During an exacerbation of allergic rhinitis, a large number of mast cells and eosinophils are present in the nasal secretion, that is, the increase in the number of these cells occurs in parallel, and during remission, the content of both decreases, but eosinophils are always greater than mast cells. When examining the nasal secretion, attention is paid to the number of goblet cells, if it exceeds 50% of all epithelial cells - this also indicates a local allergy.

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