Cough is a common symptom of respiratory disease and is usually associated with a respiratory infection when diagnosed. One type of cough that is different is cough variant asthma. According to the survey, 6% of bronchial asthma starts with frequent coughing with no wheezing symptoms, or with chest tightness that is relieved by long breaths from time to time. Although these patients are treated with antibiotics and cough suppressants, the effect is not obvious. It takes quite a long time (several months or even more than a year) for croup to appear in the lungs with shortness of breath. Such patients are highly susceptible to misdiagnosis. Diagnostic criteria for cough variant asthma: 1. Persistent or recurrent cough attacks >1 month, often at night (or early in the morning), with little sputum, aggravated by exercise. No clinical signs of infection, or ineffective with longer-term antibiotic therapy. 2. Coughing episodes can be relieved with bronchodilators. 3. There is a personal history of allergy or family allergy, the airway is hyperreactive, and allergen skin testing, etc., can be used as an adjunct.