Prolonged cough without sputum may may be caused by respiratory diseases, airway inhalation of foreign bodies, gastroesophageal reflux or tumors, or may be caused by other diseases. 1. Respiratory diseases: generally manifested as coughing up sputum, but some diseases, such as mycoplasma pneumonia, lung cancer, etc., can manifest as prolonged cough without sputum. 2. Inhalation of foreign matter in the airway: under the stimulation of foreign matter, prolonged dry cough may occur, or even repeated combination of pneumonia. 3. Gastroesophageal reflux: due to the reflux of stomach contents or stomach acid, it can stimulate the respiratory tract and lead to prolonged cough without sputum. 4. Lung tumor: if the tumor involves the airway, it can also stimulate the mucous membrane of the respiratory tract, resulting in a prolonged cough. 5. Other reasons: such as cough variant asthma, upper airway cough syndrome, drug factors can cause long-term dry cough without obvious sputum symptoms. To summarize, coughing for a long time without sputum can be seen in a variety of reasons, you need to consult a doctor in time to identify the cause, and follow the doctor’s instructions to actively treat.