Which type of cough do you have? Coughs are usually divided into 3 categories according to their duration: acute cough, subacute cough and chronic cough. Acute cough lasts <3 weeks, subacute cough 3-8 weeks, and chronic cough ≥8 weeks. A cough that lasts longer than 8 weeks without obvious evidence of lung disease is called chronic cough. Is it possible that your cough has been misdiagnosed? Acute and subacute coughs are relatively easy to diagnose, and the most common causes are post-cold cough caused by the common cold and acute bronchitis. Patients with chronic cough, on the other hand, have fewer accompanying symptoms and little abnormality on Χ-ray examination, so the misdiagnosis rate is quite high. According to a survey, about 64% of chronic cough patients have been misdiagnosed as "chronic bronchitis" or "chronic pharyngitis", with an average misdiagnosis time of 5 years and a maximum of 20 years. As a result of misdiagnosis, chronic cough patients are treated with a large number of antibiotics and some patients undergo repeated Χ-ray chest films, lung CT and fibrinoscopy due to unclear diagnosis, which not only increases the financial burden of patients but also greatly affects their quality of life. What are the causes of chronic cough? Common causes of chronic cough with normal chest radiographs include cough variant asthma, upper airway cough syndrome, eosinophilic bronchitis, gastroesophageal reflux cough, allergic cough, and drug-induced cough (e.g. ACEI-type antihypertensive drugs). What tests are done to diagnose chronic cough? If your cough has been present for more than 8 weeks, you will need to visit a pulmonary specialist for a definitive diagnosis. The first test that needs to be done is a chest Χ-ray, which can rule out some obvious lung pathologies that cause chronic cough, such as bronchopulmonary tumors, tuberculosis, and pulmonary fibrosis. For patients with chronic cough who have a normal chest X-ray, a specialist will need to perform a bronchial provocation test, induced sputum cytology analysis, 24-hour esophageal pH measurement, and nasopharyngoscopy, depending on the situation.