What causes pollinosis in children?

According to researchers, the leading role in the etiology of hay fever in children is played by pollen of cereal grasses, increased sensitivity to which was found in 75% of those examined, somewhat less often, but still quite often - tree pollen (in 56% of patients) and 27% of children were found to be sensitized to weed pollen (wormwood, quinoa). In 64% of children with hay fever, the disease develops as a result of polyvalent allergy.

Plant pollen allergens are classified as aeroallergens. Of the many thousands of plants on Earth, only about 50 produce pollen responsible for hay fever. Sensitization is caused by male reproductive elements of mainly wind-pollinated plants. The grains of these types of pollen are round and no more than 35 microns in diameter. Sensitization in each geographic zone occurs to the pollen of widespread plants that produce huge amounts of pollen (one ragweed bush produces up to 1 million pollen grains per day).

There are three main groups of allergensplants:

• woody;
• cereals;
• mixed grass (weeds).

The first spring peak of high incidence of pollen allergy (April-May) is caused by tree pollen: hazel, alder, oak, birch, ash, walnut, poplar, maple, etc. The role of pine and spruce pollen in the occurrence of allergic diseases of the respiratory tract is small.

The second summer increase in pollen concentration (June-August) is associated with the flowering of cereals: bluegrass, couch grass, brome grass, fescue, hedgehog grass, foxtail, rye, corn, etc. The flowering season of these grasses coincides with a high concentration of poplar fluff in the air, which is often mistaken by patients for a reaction to fluff.

The third autumn peak of pollen allergy (August-October) is caused by plants with the greatest allergenic activity. These include weeds: ragweed, quinoa, dandelion, hemp, nettle, wormwood, buttercup, etc.

Most of the pollen is released by plants in the morning hours (from sunrise to 9 am); the maximum concentration is in dry, windy weather.

The immunological status of children with hay fever is characterized by a high content of reagins: a high level of total IgE and specific IgE, especially during periods of pollen.

Allergic inflammation simultaneously affects the mucous membranes of the eye and nose (rhinoconjunctivitis), nose and paranasal sinuses (rhinosinusitis), nose and nasopharynx (nasopharyngitis), trachea and bronchi (rhinotracheobronchitis).

According to observations of many authors, pollinosis in children under 3 years of age occurs less frequently, in subsequent age periods the frequency of sensitization to plant pollen increases and reaches a maximum by school age. The age of the first manifestations of pollinosis in children was 3 years.

Factors predisposing to hay feverare:

• secretory IgA deficiency;
• instability of cell membranes of macrophages and granulocytes;
• reduction in the production of a substance that inhibits the activity of the pollen permeability factor,
• respiratory infections;
• environmental pollution of the atmosphere that disrupts mucociliary clearance.

The pathochemical stage of the lesion is accompanied by degranulation of mast cells of the mucous membranes of the eyes, respiratory tract with the release of a large amount of histamine and other biogenic amines. In some patients with pollinosis, immune complex mechanisms also play an active role in the pathogenesis.