1.Definition of asthma Asthma is a chronic inflammatory disease of the airways, and many cells and cytokines are involved in the development of this process. This chronic inflammation causes airway hyperresponsiveness, resulting in recurrent episodes of wheezing, dyspnea, and coughing, often at night and in the early hours of the morning, associated with widespread and variable airflow limitation, and often relieved by itself or by treatment. 2. Diagnosis, staging and classification of asthma 2.1 Diagnosis of asthma Typical asthma is not difficult to diagnose, based on recurrent wheezing, extensive dry sounds in both lungs on auscultation during attacks, and symptoms that can be relieved on their own or with bronchodilator drugs. The key is that the diagnosis of atypical asthma is difficult, with atypical clinical manifestations, which may only manifest as long-term recurrent chronic cough, mainly dry cough, waking up at night or in the early morning due to coughing, and ineffective treatment with antibiotics; or only chest tightness as the main symptom, with symptoms aggravated by cold air or special odor stimulation, and chest X-ray and ECG examination cannot find abnormalities. At this time, pulmonary function tests are very important and play the role of auxiliary diagnosis and differential diagnosis. Pulmonary function tests include bronchial diastolic test, 24h PEF daily rate of change measurement and bronchial excitation test. If the primary hospital has a spirometer or peak flow rate meter, the first two spirometry tests can be done. An improvement of FEV1 by 12% or more after inhalation of bronchodilators (or an increase of ≥200mL) and a PEF daily rate of change of ≥20% can help in the diagnosis of asthma. In primary hospitals lacking spirometers, bronchodilator test with peak flow rate meter should be promoted to assist in the diagnosis of asthma and condition monitoring. Bronchial excitation test has the risk of inducing asthma attack, and it is not suitable for this test in primary hospitals. If asthma symptoms are atypical and other cardiopulmonary diseases can be excluded and the basic lung function is normal, the patient can be advised to go to a higher level hospital for bronchial excitation test to determine the diagnosis. 2.2 Staging of asthma According to clinical manifestations asthma can be divided into acute exacerbation, chronic persistent phase and clinical remission phase. Chronic persistent phase means that symptoms (wheezing, shortness of breath, chest tightness, cough, etc.) occur at different frequencies and/or to different degrees every week; clinical remission phase means that symptoms and signs disappear with or without treatment, and lung function returns to the pre-acute attack level and is maintained for more than 3 months. 2.3 Grading of asthma 2.3.1 Grading of disease severity Chronic persistent asthma is divided into four levels according to the severity of the disease (see Table 1), which is mainly used to judge the severity before treatment or at the time of initial treatment. 2.3.2 Grading of control level Chronic persistent asthma is classified into three levels according to the level of control (see Table 2), which is mainly used to determine the severity of the disease during treatment. This grading method is easier for clinicians to grasp and helps to guide clinical treatment to achieve better asthma control. 2.3.3 Grading of acute asthma attack An acute asthma attack is the sudden onset of symptoms such as wheezing, shortness of breath, cough, chest tightness, or a sharp aggravation of existing symptoms, often with dyspnea, characterized by reduced expiratory flow, and often triggered by exposure to allergens, irritants or respiratory infections. The degree of severity varies, and the exacerbation can occur within hours or days, or occasionally within minutes, so the condition should be properly evaluated in order to provide timely and effective emergency treatment. The grading of the severity of asthma during an acute attack is shown in Table 3. 3. Treatment and management of asthma 3.1 Management plan based on clinical control of asthma The treatment of asthma in GINA 2006 is aimed at achieving and maintaining clinical control of asthma, and the treatment process is divided into 5 “steps” (see Table 4), depending on the current level of asthma control The different treatment steps are selected according to the current level of asthma control, and relief medications should be used as needed in all steps. In steps 2 through 5, multiple control medications are recommended. Treatment should be escalated if the current regimen does not result in asthma control. When the condition is controlled and maintained for more than 3 months, treatment should be gradually downgraded. It is important to note that if the increased use of relieving medications, especially if used daily, suggests that asthma is worsening, treatment should be escalated.