The onset of asthma is closely related to the change of climate, and the onset of asthma varies greatly from season to season. Many asthma patients may know this very well: every late spring (April and May) and early autumn (September and October), asthma will be aggravated, but in the hot summer and cold winter, it will be alleviated, unlike the common “old slow-onset asthma”. This is different from the common “old chronic asthma”. Causes First of all, it is the influence of temperature, humidity and air pressure. Sudden changes in temperature may affect the body’s neurological, endocrine and immune functions, easily causing the onset of the disease. High humidity can increase the body’s respiratory rate, thus triggering asthma. At the same time, high humidity can promote the reproduction of bacteria and dust mites; on the contrary, low humidity can make the respiratory mucosa dry and the airway epithelium damaged, thus aggravating the disease. Low air pressure can make various allergens such as pollen, dust mites, animal fur, bacteria, dust and industrial irritants not easily spread to high places, but easily scattered to low places and inhaled into the respiratory tract, stimulating asthma. Some thunderstorms can also increase the incidence of asthma. Secondly, late spring and early fall is the season when many plants bloom and bear fruit, and plant allergens (such as pollen) are one of the main causes of asthma onset. There are many types, densities and quantities of inhalant allergens floating in the air during spring and autumn. More than 90 species of flowering plants and plants are known to bloom in spring, including ragweed, grass, plantain and other pollens. The main cause of seasonal asthma attacks is the large amount of exposure to these allergens. The pollen season of sycamore, mulberry, willow and maple poplar in the southern coastal areas of China is in spring, thus increasing the number of asthma attacks during May-June in late spring and early summer. The pollen period of herbaceous pollen and artemisia plants (common in the north of China) is in late summer and early autumn, while seed pollen is more in late autumn, so September-November is also the peak period of asthma attacks every year. Prevention of seasonal asthma attacks requires attention to the following points: 1. Clarify the allergens that trigger asthma and try to avoid them: By recalling the medical history in detail, the factors that trigger asthma can be clarified in many cases. 70-80% of allergic asthmatics are allergic to dust mites. If the onset occurs during the rainy season, it often suggests a possible fungal allergy, and if the onset occurs in mid to late April, there may be an allergy to sycamore pollen. To identify allergens, skin tests or serum specific IgE tests should be performed at the hospital. The allergens that have been identified should be avoided or reduced as much as possible, and can even be moved to the ground for treatment. 2, avoid non-specific stimulation of the surrounding environment: such as spring, in the south is generally the rainy season, and even often thunderstorms. At this time, the air humidity is high, in addition to accelerated fungal reproduction, low air pressure, increased ozone in the atmosphere during thunderstorms, autumn and early winter, dry climate, stimulation of strong cold winds in the north of China, etc. are important non-specific stimuli that stimulate asthma attacks. Therefore, asthma patients should get into the habit of listening to weather forecasts on weather stations, increasing and decreasing their clothing according to weather changes, and taking precautionary measures (e.g., wearing a clean mask) to avoid going out in the above-mentioned weather. If you are walking on the street and are suddenly hit by strong winds, you should walk with the wind at your back to avoid being exposed to the cold air. 3. Inhibit airway allergic inflammation and reduce airway hyperreactivity: To prevent airway allergic inflammation due to seasonal inhalation of certain allergens, corticosteroids such as sodium cromoglycate and/or beclomethasone or budesonide can be inhaled before the attack season to inhibit airway allergic inflammation and reduce airway reactivity. The specific usage is to start inhaling corticosteroids about 2 weeks before the asthma attack season as prophylactic treatment, and oral or intravenous hormones should not be used as preventive medication for seasonal asthma. When seasonal allergens are identified, especially pollen and fungi, and exposure cannot be avoided, desensitization therapy can be started before the asthma attack season (preferably 2-3 months before the attack season), and maintenance doses can be administered during the attack season. If desensitization is started too late, the attack season is approaching or the asthma attack has already started.