Differential diagnosis of chronic cough: Respiratory tract infection and post-infectious cough: 1. recent history of definite respiratory tract infection. 2. cough is irritatingly dry or with a small amount of white mucous sputum. 3. no abnormalities on chest x-ray or CT. 4. normal pulmonary ventilation. 5. cough is usually self-limiting. Cough variant asthma: 1. persistent cough, often at night and/or early in the morning, aggravated by exercise or cold air, without clinical signs of infection. 2. diagnostic treatment with bronchodilators may result in significant relief of cough symptoms. 3. bronchial excitation test indicates airway hyperresponsiveness. 4. history of allergic disease and its positive family history. A positive allergen test may aid in the diagnosis. Upper airway cough syndrome: 1. The cough is worse in the early morning or when the position changes, often accompanied by nasal congestion, runny nose, dry throat, pharyngeal foreign body sensation, repeated clearing of the throat, and in a few patients, headache, dizziness, and low fever. 2. There may be pressure pain in the sinus area, yellowish-white discharge from the middle and upper nasal passages, lymphatic follicle hyperplasia in the posterior pharyngeal wall, cobblestone-like, and sometimes mucus-like attachment to the posterior pharyngeal wall. 3. Antihistamines and leukotriene receptors antagonists, nasal glucocorticoids are effective. 4, sinusitis caused by the sinuses, sinus X-rays or CT have corresponding changes. Cough due to GERD: 1. paroxysmal cough, mostly occurring at night after lying down. 2. cough mostly occurs after eating and drinking, and some patients are accompanied by upper abdominal or subxiphoid discomfort and burning sensation behind the sternum. Fiberoptic gastroscopy and 24-hour pH monitoring of the lower esophagus can confirm the diagnosis. Eosinophilic bronchitis: 1. irritant cough. 2. normal chest X-ray, normal pulmonary ventilation, no airway hyperresponsiveness. 3. relative percentage of eosinophils in sputum > 3%. 4. effective treatment with oral or inhaled glucocorticoids. Cardiac cough: 1. predominantly daytime cough that disappears when focused on something or resting at night. 2. often accompanied by anxiety symptoms. 3. not accompanied by organic disease. Psychogenic cough can only be diagnosed when tic disorders are excluded and the cough improves after behavioral interventions or psychotherapy. Treatment of chronic cough: The treatment of chronic cough emphasizes identifying the cause and treating it for the cause. Chronic cough that is accompanied by sputum should be treated with expectoration rather than pure cough suppression. H1 receptor antagonists such as loratadine and cetirizine can be used to treat upper airway cough syndrome. Patients with chronic cough clearly identified as bacterial or mycoplasma or chlamydia infections can be considered for antibiotics. Calming anti-inflammatory drugs include glucocorticoids, β2 agonists, M receptor blockers, leukotriene receptor antagonists, theophylline and other drugs, mainly used for cough variant asthma and eosinophilic bronchitis. Cough due to GERD can be treated by slightly elevating the upper half of the body while the patient is lying down and using acid suppressants and gastric motility drugs. Cough suppressants are not recommended for chronic cough, especially before the cause is identified, and codeine is contraindicated in the treatment of all types of cough. Non-pharmacological treatments include: avoidance of allergens, exposure to cold and smoke, including passive smoking; saline nasal irrigation for sinusitis; postural changes, changes in food properties, and small and frequent meals for GERD cough; prompt removal of foreign bodies from the airway; discontinuation of medication for drug-induced cough; and psychotherapy for psychogenic cough. These non-pharmacological treatments are actually highly targeted etiological treatments.