Chronic inflammatory disease of the airways involving a variety of cells, including inflammatory cells (eosinophils, mast cells, T lymphocytes, neutrophils, etc.), airway structural cells (airway smooth muscle cells and epithelial cells, etc.) and cellular components, this chronic inflammation leads to airway hyperresponsiveness in susceptible individuals, and when exposed to physical, chemical, biological and other irritants, extensive and variable reversible airflow limitation occurs This results in recurrent episodes of wheezing, coughing, shortness of breath, and chest tightness. Most of the children can be relieved by treatment or resolve on their own.
Causes
The prevalence of asthma varies between 0.01% and 32% worldwide, with a variation of nearly 300 times, and may be related to genetics, age, geographic location, climate, environment, race, industrialization, urbanization, interior decoration, standard of living, and dietary habits. The factors that trigger bronchial asthma are multiple, and the common factors can be roughly divided into two categories.
(i) external causes
There are three categories: allergens, climate change and environmental pollution, and exercise.
1. Allergens are broadly divided into three categories.
① Infectious pathogens and their toxins: pediatric asthma attacks are often closely related to respiratory infections, the main pathogens are respiratory viruses, such as syncytial virus (RSV), adenovirus, influenza, parainfluenza virus, etc. It has been proved that syncytial virus infection can occur due to the occurrence of specific IgE-mediated type I metaplasia and wheezing, other local infections such as sinusitis, tonsillitis, dental caries, etc. may also be triggering factors Other local infections such as sinusitis, tonsillitis and caries may also be triggering factors.
②Inhalants: usually inhaled from the respiratory tract, domestic application of skin tests show that the most important allergens causing asthma are dust mites, house dust, mold, polyvalent pollen (Artemisia, ragweed), feathers, etc. There are also reports of contact with silkworms to develop asthma, especially mites as inhalation allergens, occupy an important position in respiratory allergic diseases, childhood allergy to mites than adults, spring and autumn is the most suitable for the survival of mites. In addition, asthma attacks caused by inhalation allergens are often related to the season, region and living environment, and the symptoms can be reduced or disappeared once the exposure is stopped.
③Food: mainly heterogeneous proteins, such as milk, eggs, fish and shrimp, meat, peanuts, sesame, flour, corn, and various vegetables, as well as strawberries, sets, mangoes, pineapples and other fruits, spices, etc. Food allergy is common in infancy and gradually decreases after the age of 4 to 5 years.
④ Non-specific stimuli: such as cold air, paints, pesticides such as DDV, oil, coal and cigarette smoke, cosmetics, sulfur dioxide, automobile exhaust, jewelry containing nickel, chromium, etc., preservatives, coloring agents, flavoring agents of salty and sweet foods, etc.
⑤ Drugs: antipyretic and analgesic drugs such as aspirin, β-blockers such as Thaumatin, penicillin, sulfonamides, etc.
2.Climate change and environmental pollution
Such as low atmospheric pressure and high humidity before thunderstorms, seasonal changes, large temperature changes, typhoons are good time for asthma, organic floating dust and particles in the air, such as hazy weather can also trigger asthma.
3.Exercise
Foreign reports about 90% of children with asthma, exercise can often trigger asthma, also known as exerciseinduced asthma (EIA), mostly in older children, vigorous and sustained (more than 5-10 minutes) after running is most likely to induce asthma. Some children can also induce asthma after size and crying.
(II) Internal causes
There are several aspects.
1.Heredity
This has been recognized as the main cause, the genetic mode is complex, for polygenic inheritance, individual autosomal inheritance. Most asthma patients have atopic qualities, such as eczema, allergic rhinitis, drug and food allergies, etc.
2.Immune dysregulation
The balance between Th2 cytokines such as IL-4 and IL-5 and Th-1 cytokines such as IFN-γ and IL-2 is disturbed, which is the most prominent and basic immunological change in asthmatic patients. We have found after years of research that asthmatic patients have reduced CD8+ function and quantity, relatively hyperactive CD4+, increased CD4+/CD8+ ratio, decreased percentage of erythrocyte B3b receptors (RBC-C3bR), high percentage of erythrocyte immune complexes (RBC-IC), imbalance of IgE, IgD, IgG, subclasses and complement components, resulting in enhanced allergic response of the organism and The anti-infection function decreases, thus making it easy for allergic diseases and respiratory tract infections to occur, resulting in recurrent asthma attacks.
3.Imbalance of endocrine function
We found that estradiol is elevated and cortisol, testosterone and progesterone are decreased in asthma patients, and the changes are related to cellular immunity. The higher the estradiol, the lower the cellular immunity. In conclusion, endocrine factors, especially changes in sex hormones, are factors closely associated with the regression of asthma around puberty. The partial remission or exacerbation of asthma during menstruation, pregnancy, lactation and menopause is also a strong evidence of the involvement of endocrine hormones in the development of asthma.
4.Mental and neurological factors
Drastic changes in mood, strong mental stimulation, panic, depression, sadness, excessive stress and fatigue can trigger asthma, and even conditioned reflexes and other high-level neural activities are related to asthma.
5.Plant nerve dysfunction
Asthma patients have relatively low sympathetic nerve function and relatively high sympathetic nerve function.
6, other: zinc and other trace elements deficiency or imbalance, vitamin A, D, C and other deficiencies are also directly related to the development of asthma.