What are causes of chronic cough?

Some common causes of chronic cough include asthma, allergic rhinitis, sinus problems (for example sinus infection), and esophageal reflux of stomach contents. In rare occasions, chronic cough may be the result of aspiration of foreign objects into the lungs (usually in children). It is very important to see a doctor who may order a chest X-ray if a chronic cough is present. The following are common causes of chronic coughing.

• Cigarette smoking actually is the most common cause of chronic cough.
• Asthma is a disease of airways, resulting in difficulty breathing orwheezing often characterized by abnormal breathing tests. Some asthma sufferers have chronic cough as their only symptom. They may even have normal lung functions tests. This is often referred to as cough-variant asthma. Asthma symptoms can be aggravated by cold air, exposure to air pollutants or pollen, smoke, or perfumes.
• Gastroesophageal reflux disease (GERD) refers to acid reflux, or backward flow, of stomach acid and other contents into the esophagus. If stomach acid moves backward up the esophagus, reflexes result in spasm of the airways that can cause shortness of breath and coughing. In some instances, acid reflux can be so severe that substances can be aspirated into the lungs and cause similar symptoms as well as damage to lung tissue. In some individuals, no sensation of heartburn is felt and their only symptom may be cough.
• Sinus problems and postnasal drip can also cause chronic cough with mucus. This condition can be difficult to detect. Sometimes CT scan of the sinuses is necessary for diagnosis. Affected individuals often complain of a "tickle in their throat" and frequent throat clearing.
• Infections such as bronchitis or pneumonia can cause acute cough or a chronic cough. These infections can be caused by viruses, bacteria, or fungus. Viral infections do not respond to antibiotics. In patients with asthma, viral upper respiratory infections often result in a protracted cough even after the infection has cleared.
  • A particular strain of bacterial pneumonia, called Mycoplasma, may cause a chronic cough with fatigue, weakness, shortness of breath, and sputum production. This infection is sometimes referred to as "walking pneumonia," and commonly affects young and relatively healthy people.
  • Whooping cough (pertussis) is an acute, highly contagious respiratory infection caused by the bacterium Bordetella pertussis.Whooping cough commonly affects infants and young children, but can be prevented by immunization with pertussis vaccine. In adults, whooping cough can be a cause of chronic cough.
• Chronic cough in children is uncommon. Foreign material obstructing the airways of the lungs, asthma, and allergies are evaluated by a pediatrician.
• Certain medications, notably ace inhibitors (enalapril [Vasotec],captopril [Capoten] etc.) used in treating high blood pressure, can cause chronic cough.
• Less common causes of chronic cough include allergies, tumors,sarcoidosis, congestive heart failure, or other lung diseases such aschronic obstructive disease (COPD) or emphysema.

If chronic cough persists it is extremely important for the affected individual to be evaluated by a doctor. The doctor will consider the possibility of asthma, postnasal drip, esophageal reflux, drug side effect, interstitial lung disease, or other unusual infections.