The causes of dry cough without sputum and prolonged coughing include: cough variant asthma, postnasal drip syndrome, chronic pharyngitis, tuberculosis, lung cancer, etc. 1. Cough variant asthma: this disease belongs to the special type of bronchial asthma, often in contact with pollen, dust mites, animal hair and other allergens induced cough, mostly at night irritating dry cough is the main, if there is no timely detachment from the allergen, can appear dry cough for a long time without healing the phenomenon. 2. Postnasal drip syndrome: Postnasal drip syndrome can also cause chronic cough, mainly due to the nasal cavity in the secretions continue to flow into the throat, so that the throat is stimulated due to the early more than a dry cough is the main, if you do not take timely and effective treatment, there will be a pronounced cough sputum. 3. Chronic pharyngitis: patients with chronic pharyngitis may experience recurrent itching, pain, burning sensation, foreign body sensation, the pharyngeal mucosa continues to be stimulated, and therefore may be manifested as a dry cough for a long time. 4. Tuberculosis: dry and prolonged cough may also be related to tuberculosis, especially when combined with night sweats, weakness, emaciation, low afternoon fever and other phenomena, the possibility of tuberculosis is greater. 5. Lung cancer: One of the early symptoms of lung cancer also includes prolonged irritating cough. Especially if there are patients with a long history of smoking, and at the same time, there are persistent fever, chest pain, hoarseness, and blood in the sputum, then it is necessary to be alert to the possibility of lung cancer. There are many other reasons for prolonged dry cough, such as eosinophilic bronchitis, gastroesophageal reflux stimulating cough, pulmonary fibrosis, it is recommended to go to the hospital as soon as possible to find out the reasons and follow the doctor’s instructions for treatment, so as not to cause serious consequences.