Chronic Cough

Coughing is a symptom of asthma, a disease that should be monitored by a doctor.Source: Getty Images

Some common causes and risk factors for chronic cough include asthma, allergic rhinitis, sinus problems (for example sinus infection), esophageal reflux of stomach contents, medications such as ACE inhibitors, and whooping cough. In rare cases, chronic cough may be the result of inhaling foreign objects into the lungs (usually in children). It is important to see a doctor who may order a chest X-ray if a chronic cough is present. Common causes of chronic cough include:

• Cigarette smoking is the most common cause of a constant, chronic cough.
• Asthma is a disease of the airways, resulting in difficulty breathing or wheezing 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, 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 inhaled (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 chronic cough.
• Sinus problems and postnasal drip also are causes of 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. The common cold and the flu often produce a dry cough. Viral upper respiratory tract infections often result in a prolonged cough even after the infection has cleared in people with asthma. Acute bronchitis and chronic bronchitis are common causes of coughing up blood (hemoptysis).
• 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 healthy people.
• Whooping cough (pertussis) is an acute, highly contagious respiratory tract infection caused by the bacterium Bordetella pertussis. It can cause violent, rapid, constant coughing (often a high-piched cough with a “whoop” sound at the end) and it can be life-threatening in young children. 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 need to be evaluated by a pediatrician.
• Certain medications, like 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 as chronic obstructive disease (COPD) or emphysema. Lung diseases also can cause coughing up blood.

If chronic cough persists, it is important to be evaluated by a doctor. The health-care professional will consider the possibility of asthma, postnasal drip, esophageal reflux, drug side effects, interstitial lung disease, lung cancer, or other unusual infections.