I. Diagnostic criteria for asthma in infants and children 1. age “3 years”, ≥ 3 wheezing episodes; 2. hearing whistling sounds in both lungs during the attack, prolonged expiratory phase; 3. having atopic physique, such as allergic eczema, allergic rhinitis, etc.; 4. parents have a history of allergy such as asthma; 5. except other diseases causing wheezing. With 1, 2, 5 can be diagnosed as asthma. If there are only 2 episodes of wheezing, but there are items 2 and 5, the diagnosis is suspected asthma or wheezing bronchitis. If there are both 3 and/or 4, a therapeutic diagnosis of asthma can be considered. The diagnosis of asthma in children is based on the following criteria: 1. the age of 3 years old, recurrent attacks of wheezing (or can be traced to some allergens or irritants); 2. the exhalation-phase whistling sound is heard in both lungs during the attack, and the exhalation phase is prolonged; 3. bronchodilators have obvious effect; 4. other diseases causing wheezing, chest tightness and cough. Bronchodilator test can be done in all age groups with suspected asthma and whistling sound in the lungs as follows: 1. 1‰ epinephrine 0.01ml/Kg subcutaneously, the maximum amount should not exceed 0.3ml/time; 2. salbutamol aerosol or solution nebulized inhalation. After doing any of the above tests for 15 minutes, if the wheezing is significantly relieved, the lung whistling sound is significantly reduced, or the FEV1 rises ” 15%, it is a positive bronchodilator test and can be diagnosed as bronchial asthma. C. Diagnostic criteria for cough variant asthma (regardless of age) 1. Persistent or recurrent cough attacks >1 month, often at night (or early morning), with little sputum and aggravated by exercise. There are no clinical signs of infection or longer-term antibiotic treatment is ineffective; 2. The use of bronchodilation and can relieve coughing attacks (basic diagnostic condition); 3. There is a personal history of allergy or family history of allergy, positive allergen test, etc. (auxiliary diagnostic condition); 4. Airway hyperresponsiveness characteristics, positive bronchial excitation test (auxiliary diagnostic condition); 5. Except for other causes of chronic cough.