Allergic cough needs to check pulmonary ventilation function, induced sputum eosinophil count, allergen skin test, serum total IgE or specific IgE. 1. Pulmonary ventilation function: including lung volume examination, ventilation function examination, gas exchange function examination, small airway function examination, lung diffusion function measurement, airway resistance measurement, bronchodilator test, bronchial excitation test, exercise cardiopulmonary function test, etc.. Allergic cough with normal pulmonary ventilation and negative bronchial provocation test. 2. Induced sputum eosinophil count: sputum production is induced by inhalation of nebulized hypertonic saline and sputum is further analyzed for eosinophils, which is not high in allergic cough. 3. Allergen skin test: Allergen is injected into the skin and the diameter of the erythema or wind spot is observed. The test is positive for allergic cough. 4. Total serum IgE or specific IgE: Adult serum IgE levels range from 20 to 200 IU/ml, and are generally considered abnormally elevated when greater than 333 IU/ml (800 ng/ml). Specific IgE is IgE that binds specifically to a particular allergen. allergic cough has an elevated value for this test. Allergic cough patients also need to check the exhaled breath nitric oxide measurement, blood routine, etc. It is recommended to go to the hospital as soon as possible, follow the doctor’s instructions to improve the relevant examinations, and carry out regular treatment.