Etiology of pollen allergic rhinitis

The incidence of allergic rhinitis and asthma caused by pollen sensitization has increased significantly, involving 40% children aged 6-7. Studies have shown that pollen is the main factor to promote the increase of respiratory allergic diseases, especially in the suburbs of industrialized cities. Studies on allergic rhinitis caused by pollen in summer and autumn in China show that 53% patients are complicated with allergic asthma. The onset seasons of allergic rhinitis and asthma are mostly concentrated from mid-August to the end of September. A few patients have paroxysmal rhinitis and asthma in late August when the pollen concentration in the air is the highest. Most patients complain that in sunny or windy days, the symptoms of allergic rhinitis will be aggravated frequently, while in rainy days, the symptoms of allergic rhinitis and asthma will be alleviated, and a severe asthma attack can be induced after a storm.

Artemisia pollen and Artemisia pollen are the most common allergic pollen in summer and autumn in northern China. Artemisia pollen and Artemisia pollen are generally 20-30 μm in diameter. The air pollen monitoring shows that the peak of pollen in summer and autumn is from mid-August to mid-September (the peak of Artemisia pollen count is close to 300 grains/1000mm2, and the peak of Artemisia pollen count is close to 800 grains/1000mm2).

In early August, patients with pollen allergy will have symptoms of rhinoconjunctivitis, sneezing and runny nose in summer and autumn. The most obvious symptoms are conjunctivitis, inexplicable itchy eyes, redness and tears. In mid-August, the symptoms of rhinitis and conjunctivitis continued to worsen, and some patients developed asthma symptoms of persistent cough and wheezing at night.

In summer and autumn, patients with pollen allergic asthma attack asthma in late August when the air pollen concentration is the highest, which generally lasts 10-20 days. Throughout the pollen season, allergic asthma patients can't lie flat at night, and 80% need to be hospitalized. In recent years, it has been found that more than 47% of patients with pollen allergic rhinitis in summer and autumn in China will develop seasonal allergic asthma within 9 years.

Climate affects asthma attacks.

Climatic factors may be one of the reasons why pollen in the north is easy to cause asthma. It is believed that environmental factors such as automobile exhaust, dust and asthma have little to do with it, but relative humidity, air pressure, fog and rain can affect the hospitalization rate of adults and even children, because higher temperature and humidity can stimulate pollen particles to release allergen active particles into the air at the same time, and airborne allergen particles in the air before and after pollen season can also lead to pollen allergic rhinitis, conjunctivitis and asthma.

There are two kinds of cells in the human body, namely mast cells and basophils, which are widely distributed around microvessels in nasal mucosa, gastrointestinal mucosa and connective tissue under the skin, as well as in the capsule of internal organs. These two types of cells contain allergic mediators such as histamine, leukotriene, 5- hydroxytryptamine and elimination. Stimulated by environmental factors such as chemicals, air pollution and sunlight radiation, a large number of free radicals will be produced in the body. If free radicals are not removed in time after oxidation, the cell membranes of mast cells and basophils will be destroyed and denatured, leading to cell instability. When unstable cells encounter allergens, antigens and antibodies react specifically, resulting in cell membrane detachment and release of allergic mediators. Allergic media can cause smooth muscle contraction, telangiectasia, enhanced permeability, mucus secretion and tissue damage, thus triggering allergic reactions. In the process of allergic reaction, allergic mediators play a direct role, allergens are the external causes of allergic diseases, while the body's immune ability is low, and the oxidative damage of a large number of free radicals to mast cells and basophils is the internal cause of allergies. In addition, according to the theory of traditional Chinese medicine and the latest research results, allergies are mainly caused by wind, dampness, heat and evil in blood and skin, or by blood heat and exogenous wind. That is, it has a considerable relationship with some toxins contained in human blood.

The oily and polysaccharide substances contained in pollen will be digested by nasal secretions after being inhaled by people, and then more than ten kinds of antibodies will be released. If this antibody meets the invading pollen and accumulates in large quantities, it will cause skin allergy. According to expert research, there are two main reasons: on the one hand, due to the improvement of people's living standards, a large number of high-protein and high-calorie foods such as eggs and meat products are ingested in the diet, which leads to the hyperactivity of antibodies in the body, so when encountering antigens such as pollen, allergic reactions are more likely to occur. On the other hand, due to air pollution, water pollution and the extensive application of food additives, people are exposed to more antigenic substances, which leads to allergic diseases.