Causes of a persistent cough include asthma, postnasal drip, chronic bronchitis or gastroesophageal reflux disease, according to Mayo Clinic. Upper respiratory tract infections and angiotensin-converting enzyme inhibitors used to treat hypertension can also cause a persistent cough. Other causes are chronic obstructive pulmonary disease and lung cancer.
A persistent cough can also be caused by inhaling a foreign body or food, cystic fibrosis and sarcoidosis, explains Mayo Clinic. Bronchiectasis and bronchiolitis are other conditions that can lead to a persistent cough.
Bronchiectasis is a condition where the bronchial tubes in the lungs become stretched and dilated due to the secretion of mucus, notes the American Lung Association. It can be caused by injury or be a complication of an illness such as tuberculosis. Bronchiolitis is a lung infection caused by a virus. It is almost always seen in babies and young children and occurs mostly in winter.
Cystic fibrosis is a hereditary condition where mucus producing glands, including the lungs, produce abnormal mucus, according to the Cystic Fibrosis Foundation. As of 2015, it is considered incurable. Sarcoidosis is a disease where nodules called granulomas grow in the lungs or lymph glands, states WebMD. The malady causes an unproductive cough, shortness of breath and fatigue.