The onset and recurrence of asthma is due to a complex combination of factors, most of which are genetically based and triggered by external and internal factors. The main triggering factors are as follows:
1, allergens.
(1) Specific antigens:
Pollen: Asthma caused by inhalation of pollen, called pollen asthma, is caused by inhalation of certain allergenic pollen in certain areas and seasons, and causes seasonal attacks or seasonal aggravation of bronchial asthma. In typical cases, the first symptoms appear in a certain month, mostly precursors such as chytridiomycosis, and then gradually form paroxysmal attacks. The duration of the attack of simple asthma caused by a certain kind of flower is generally determined by the length of the pollen period, and the symptoms of the attack are no different from those of typical bronchial asthma, and the effect of medication is very poor. The symptoms during an attack are similar to those of typical bronchial asthma, and medication is ineffective. Pollen as an allergen must have the following five conditions:
①More production;
② Good at floating in the air and suitable for long-distance flying;
③ Contains allergenic toxicity;
④The plants that produce these pollens are mainly wind-borne types;
⑤ These plants are widely distributed in the local area. Thus, for spring-type or autumn-type hay fever patients, different allergens can be selected for skin testing and desensitization treatment.
Dust: Various types of dust can often trigger or aggravate an asthma attack. Organic dusts can be irritating and can also be immune-mediated and cause reactions. Household dust is composed of various components, mainly decaying material, bedding, clothing, flakes from worn out furniture, dander, bacteria, mold, etc. Some allergic patients may have an immediate positive reaction to a crude dust leachate skin test, but dust from different sources contains a variety of different components.
Dust mites: Dust mites breed in the human living environment, such as bedrooms, mattresses, pillows, sofas, clothes, etc. There are also mites in school floors, cotton mills, flour mills, food warehouses, etc. The incidence of mite allergy is higher in children than in adults, and higher in men than in women.
Epidermal allergens: Type I allergic diseases caused by dander from dogs, cats and horses are well known. While the fur of dogs and cats is not an important allergen, their dander is an important allergen. Allergies to cattle, pigs, horses and sheep should be noted in rural areas. Animal house keepers or animal experimenters should pay attention to allergies to rabbits, rats, mice, guinea pigs, dogs, monkeys, cats, etc. Others such as down jackets, duvets and woolen sweaters should also be taken seriously.
Mold: Van Leeuwen first studied the relationship between mold and asthma in 1924. Humid air or dwelling room mold easy to produce out. The literature by the interstitial mycobacteria caused by asthma, a lot of records, the use of its leachate for desensitization therapy on the kind of mold special allergy patients, can be effective. But contraindicated desensitization with the mold.
Insect excrement: beetles, locusts, moths, weevils in beans, mites in the valley, cockroaches excrement can cause type I allergic reactions and cause asthma attacks. There is experimental evidence that excreta are allergenic bioactive substances.
(2) non-specific factors: industrial gases, ammonia, gas, oxygen, methane, cold air, sulfuric acid, etc. can induce asthma.
2, whistle infection: whistle infection has an important relationship with asthma. Many asthma patients in the respiratory tract infection wheezing increased, more obvious in children. Early epidemiological investigations have shown that viral whistle infections can aggravate asthma. The mechanism that triggers asthma is multifactorial, and available data suggest that viral whistle infections appear to have the potential to enhance the anti-inflammatory effects of the airways, a factor that is similar to the pathogenesis of asthma.
3, climate factors:
① temperature: sudden changes in temperature may be an irritant, just as general asthma patients inhale gas or other irritant gases, asthma immediately after the attack. Some people believe that the climate and environmental changes to the human body is a “stress”, this stress can affect the human nervous system, endocrine, body fluids in the acidity, potassium and calcium balance and immune mechanisms.
②Humidity: too high humidity can affect the evaporation of water from the body surface, and the body will speed up inspiration to compensate for it, which is harmful to asthma. On the other hand, too low humidity can dry out the mucous membrane of the whistle and cause asthma attacks. Exercise asthma is characterized by dry airways. It is generally believed that the ideal humidity level should be 35% to 50%. It is difficult to elucidate the mechanism of humidity to stimulate asthma, but it is generally believed that bacteria and molds can easily grow and multiply in humid air, thus easily causing whistle infection and triggering asthma.
③ Air pressure: when the air pressure is low, various allergens such as pollen, mold, bacteria, dust and industrial irritants are not easy to drift or fly high, so it is easy to be inhaled.
Air ions: Some authors believe that the symptoms of allergic reactions are not due to changes in temperature, humidity and air pressure, but may be due to the presence of ions in the air.
4, drug factors: drug-induced asthma is not uncommon, clinically used drugs such as tinctures containing phlegm cough drops, sulfonamides, aspirin, penicillin, insulin, local anesthetics, etc., so in the treatment must ask the patient’s drug allergy history.
Agarwal reported that 15% of asthma cases were induced by psychiatric factors alone, 50% by psychiatric factors combined with allergic reactions, and only 2% to 5% by depressive disorders in the general population. The biopsychosocial medical model of asthma is influenced by the interaction of biological (biological), psychosocial (psychological) and social factors. The overlap between asthma and apprehension in biology and pathophysiology should be studied in more depth, and clinical examples of asthma attacks triggered by mental stress, fear and anxiety are often seen. Mental factors not only have the role of triggering asthma, but also can produce therapeutic effects.
6, exercise factors: exercise-induced asthma, also known as exercise-induced asthma, refers to a certain amount of exercise after the emergence of acute, temporary small and large airway obstruction. Clinically, acute attacks of asthma of varying severity are the main manifestation, and can mostly relieve themselves. Exercise asthma occurs mainly in people with a history of asthma or a family history of asthma and can occur at any age, with almost equal incidence in adults and children. In general, patients with acute exacerbation asthma or a recent history of acute exacerbation can be induced with appropriate excitation tests and more sensitive pulmonary function measurements near maximum exercise.