1. Cough variant asthma (CVA): CVA is the most common cause of chronic cough in our children, especially in preschool and school-age children. It is usually a dry cough, which often attacks at night and/or early in the morning and is aggravated by exercise and cold air, with no clinical signs of infection or after a longer period of ineffective antibacterial drug treatment. Significant relief of cough symptoms with diagnostic tracheodilator therapy; normal pulmonary ventilation and bronchial excitation test suggesting airway hyperresponsiveness; history of allergic disease, and positive family history of allergic disease. Positive allergen testing may aid in the diagnosis. 2. Upper airway cough syndrome (UACS): common in preschool and school-age children. Until 2006, the diagnostic name for UACS was postnasal drip syndrome. The cough is accompanied by white foamy sputum (allergic rhinitis) or yellow-green pus sputum (sinusitis), and is worse in the morning or with changes in position, accompanied by nasal congestion, runny nose, dry throat with foreign body sensation and repeated clearing of the throat; the follicles in the posterior pharyngeal wall are markedly hyperplastic, sometimes with cobblestone-like changes, or with mucus-like or purulent secretions; antihistamines, leukotriene receptor antagonists and nasal glucocorticoids are effective in chronic cough caused by allergic rhinitis. Chronic cough caused by allergic rhinitis is effective, and chronic cough caused by purulent sinusitis requires antibacterial medication for 2-4 weeks; nasopharyngoscopy or lateral head and neck radiographs, sinus radiographs or CT films can be helpful for diagnosis. 3. Post-infectious cough (PIC): a common cause of chronic cough in young children and preschoolers with a recent clear history of respiratory tract infection; an irritating dry cough or with a little white mucous sputum; chest X-ray examination without abnormalities or showing only increased texture in both lungs; normal pulmonary ventilation or showing a transient airway hyperresponsiveness, with a cough that is usually self-limiting. 4. Gastroesophageal reflux cough (GERC): 24-hour lower esophageal pH monitoring is the gold standard for the diagnosis of GERC, but it is difficult to complete the operation, thus probably underestimating the incidence of GERC in China. The best time phase for paroxysmal cough is at night; the cough can also intensify after eating with a positive 24-hour lower esophageal pH monitoring. 5. psychogeniccough: Psychogenic cough in children should be diagnosed only when multiple tics are excluded and the cough can be improved after behavioral intervention or psychotherapy; it is common in school-age and adolescent children, and is more common in older children; daytime cough is predominant, and the cough disappears when focused on something or resting at night; it can be a goose-like, high-pitched cough; it is often accompanied by anxiety symptoms, but not with organic disease. 6. Non-asthmatic eosinophilic bronchitis (NAEB): the diagnosis of this disease is not high because the technique of induced sputum and eosinophil count are not yet widespread in pediatrics. Relative percentage of eosinophils in sputum > 3%; bronchodilator therapy is ineffective and oral or inhaled glucocorticoid therapy is effective. 7. Allergic cough (AC): Clinically, certain children with chronic cough have atopic constitution and effective treatment with antihistamines and glucocorticoids, but they are not bronchial asthma, CVA or NAEB, etc. This type of cough is referred to as allergic (allergic) cough in the literature. It presents with an irritating dry cough; normal pulmonary ventilation, negative bronchial excitation test, increased sensitivity of cough receptors, history of other allergic diseases, positive allergen skin test, and elevated total and/or specific serum IgE. 8. Drug-induced cough: Although uncommon in children, they should still be alerted. Drugs such as angiotensin-converting enzyme inhibitors and β-adrenergic receptor blockers such as Tretinoin can induce a chronic cough, which usually manifests as a persistent dry cough that worsens at night or when lying down, and the cough is significantly reduced or even disappears 3-7 d after stopping the drug. 9. Otogenic cough: 2%-4% of the population have vagal nerve branches, and when lesions occur in the middle ear, stimulation of the vagus nerve can cause a chronic cough. Otogenic cough is a rare cause of chronic cough in children.