Cough variant asthma, also known as allergic cough, is a specific manifestation of asthma, mainly characterized by persistent or recurrent cough attacks for more than one month, often with nocturnal or early morning episodes of cough, low sputum, aggravated by exercise, no clinical manifestations of infection, or ineffective after prolonged antibiotic treatment, with bronchodilators to relieve the cough attacks, often with personal or family allergies. Cough variant asthma is characterized by: 1. persistent or recurrent coughing attacks for more than one month, often occurring at night or in the early morning, aggravated by exercise, with little sputum; 2. no obvious signs of infection or ineffective after prolonged antibiotic treatment; 3. the attacks can be relieved with bronchodilators; 4. a personal history of allergies, i.e., with a history of eczema, urticaria, allergic rhinitis, etc., or a family history of allergies can be identified; 5. Family history of allergy can be found; 5. Exercise, cold air, allergens or viral infections trigger asthma attacks; 6. Asthma is seasonal, mostly seen in spring and autumn and recurrent; 7. Chest X-ray shows normal or increased lung texture but no other organic changes. In children with cough variant asthma, there is persistent metabolic inflammation in the respiratory tract and swelling of the bronchial epithelium, which makes the excitation threshold of the subcutaneous stimulus receptors in the airways lower than normal, so that the induction of various external stimuli is increased and coughing occurs at the slightest stimulus, i.e., airway hyperresponsiveness; and the cough is difficult to cure.