Definition of chronic cough Coughs are usually divided into 3 categories according to their duration: acute cough, subacute cough and chronic cough. Acute cough <3 weeks, subacute cough 3-8 weeks, and chronic cough >8 weeks. Chronic cough has many causes and is usually divided into 2 categories according to the presence or absence of abnormalities on chest X-ray: one category is those with definite lesions on X-ray chest films, such as pneumonia, lung cancer and tuberculosis; the other category is those with no obvious abnormalities on X-ray chest films and cough as the main or only symptom, which is usually referred to as unexplained chronic cough (referred to as chronic cough). Clinically, a cough lasting longer than 8 weeks with cough as the main manifestation and no obvious lesion on chest X-ray is usually referred to as chronic cough of unknown origin, or chronic cough for short. These chronic cough patients have a high rate of misdiagnosis and misdiagnosis due to few accompanying symptoms and no abnormalities on X-ray, and a large number of patients are misdiagnosed as “bronchitis or chronic pharyngitis”. PNDS), eosinophilic bronchitis (EB), eosinophilic bronchitis (EB), allergic cough (AC), and gastroesophageal reflux cough (GERC). Therefore, chronic cough is not always associated with chronic bronchitis. Chronic bronchitis accounts for less than 4% to 8% of chronic cough patients seen in outpatient clinics, and more often for a number of other conditions such as gastroesophageal reflux, cough variant asthma, eosinophilic bronchitis, and postnasal drip syndrome. These diseases account for 70% to 95% of chronic coughs in outpatient clinics Gastroesophageal reflux disease: It is a cough caused by reflux of gastric acid and other food from the stomach into the esophagus, and patients often have heartburn, acid reflux,. Belching and other reflux symptoms are common in patients with gastric ulcer and duodenal ulcer. Cough variant asthma: characterized by nocturnal cough, mainly manifested as an irritating dry cough (mostly occurring at night or in the early morning), but without typical asthma symptoms such as wheezing and shortness of breath. Cold, cold air, dust, and oil smoke can trigger or aggravate the cough. Cough variant asthma: characterized by nocturnal cough, mainly manifested as irritating dry cough (mostly occurring at night or in the early morning) and sputum, which are not abnormal when X-ray or chest CT examination or pulmonary function tests are done in these patients. Postnasal drip syndrome: The cough is caused by nasal disease that causes secretions to flow backwards into the postnasal and throat areas. Patients have frequent throat clearing, throat itching discomfort or nasal itching, nasal congestion, runny nose, sneezing, and even hoarseness. Common causes include common cold, rhinitis (especially allergic rhinitis), sinusitis, nasal polyps, etc. Find the right cause for chronic cough. Don’t abuse antibiotics. Except for a few chronic coughs related to bacterial infections, the use of cough medicines or antibiotics alone is not only ineffective, but can even further aggravate the condition. There are many different causes of chronic cough, and if you treat it without finding the right cause, chronic cough often cannot be cured. Empirical treatment of chronic cough Empirical treatment of chronic cough means that in cases where the diagnosis of the cause is uncertain, corresponding therapeutic measures are given according to the condition and the possible diagnosis, and the diagnosis is established or excluded by the response to treatment. Those who fail to respond to empirical treatment should promptly go to a hospital in a position to perform relevant tests to clarify the cause. Close follow-up should be performed to avoid missing early bronchial malignancies, tuberculosis and other lung diseases.