The Medical Minute: Coughs - a common symptom with many causes

September 01, 2004

By John Messmer
Penn State Milton S. Hershey Medical Center
Penn State College of Medicine

What is the best thing you can do for a cough? It depends. A cough is a symptom, not an isolated problem. The best way to treat a cough is to treat the underlying cause rather than simply suppressing it.

Cough is the fifth most common symptom for which people seek treatment. In excess of $600 million is spent annually on over-the-counter cough medication. The most common causes of cough are respiratory infections, such as colds, sinusitis, bronchitis or pneumonia, but there are many other reasons why people cough.

Usually, coughing serves to clear irritants from the airways. In respiratory infections, coughing moves mucus from infected areas. For that reason, total suppression of the cough is usually not recommended.

The tricky part of treating coughs is diagnosing the conditions that might be contributing to it. When a cough lasts longer than three weeks, it is considered chronic, but even a viral upper respiratory infection can inflame the airways enough that it can take up to seven weeks for the cough to stop.

Smoking is a major cause of chronic coughs. Smokers expect to cough, but people who are around smokers can cough, even if the smoking is only done outside.

Pollen and mold can cause problems for people allergic to them, but postnasal drainage from inhaled pollen can trigger a cough even in non-allergic people. Other possible irritants include dust; flowers; perfume and cologne; chemical fumes from household cleaners, auto exhaust, and factories; and pet and plant odors.

Asthma may present as a cough rather than wheezing. This type of cough typically worsens with exertion and cold weather and may include shortness of breath.

Medications, particularly angiotensin converting enzyme (ACE) inhibitors and sometimes beta blockers cause cough. These medications are typically used for high blood pressure and heart disease.

Gastroesophageal reflux is usually associated with heartburn, but it is a common cause of cough even without heartburn. Tiny volumes of stomach fluids move back up the esophagus to the throat where they irritate the upper airway triggering a cough.

Chronic bronchitis is a persistent inflammation of the airways, commonly as a result of years of smoking having destroyed the normal mechanism for moving mucus out of the lungs. Mucus thickens and provides a continuous irritant for the airways and thus a chronic cough. In bad cases, sections of lung become completely ineffective and simply accumulate mucus and bacteria, a condition known as bronchiectasis.

Children can have croup, a viral inflammation of the airways, typically causing a cough described as "barking." Whooping cough occurs in children who have not received vaccination against it. It causes such severe inflammation in the very small airways of children that the violent coughing they do has a "whooping" sound. Children less than 6 months old can contract respiratory syncytial virus in wintertime. It causes significant shortness of breath along with a cough.

Less common causes of cough, but still very important to determine, are heart failure and heart valve disorders, lung cancer and scarring conditions of the lungs and tuberculosis. Occasionally a cough is just a habit. Older people can develop a pocket in the esophagus that leads to regurgitation of fluid and aspiration into the airways at night causing a cough. Finally, foreign material may have been inhaled and trapped in an airway.

So, what is the best thing to do for a cough?

Smokers may not be able to eliminate the cough for months even if the smoking itself is not the primary problem. Quitting smoking is the first step in treatment.

If you have stuffy nose, sore or scratchy throat and clear to cloudy mucus with low or no fever you may have a cold. The cough comes from drainage and a decongestant is the best approach to treatment although some people do not tolerate them. Dextromethorphan, a derivative of codeine, is the standard over-the-counter cough suppressant, but some people do not metabolize it properly so it does not work for them. Some people are very susceptible to the narcotic side effects of dextromethorphan.

Other cough medications have antihistamines that have minimal effect on some people and no cough suppressant effect at all on many. Many cough medications have enough alcohol in them to cause sedation rather than cough suppression. You may get as much benefit from sipping tea with honey and lemon or using a mentholated cough drop. The most effective suppressants are typically prescription strength narcotics, but before prescribing one, your doctor will need to be comfortable that suppressing the cough will not make you worse.

If you are coughing up brown, green or yellow mucus, you could have a bacterial infection. High fever can result from influenza or pneumonia during the winter. Shortness of breath can be from infection, asthma or heart disease. Leg swelling may mean heart failure. Bloody sputum could result from forcible coughing, drainage from sinusitis, airway irritation from bronchitis or it could be due to chronic airway disease, lung cancer or tuberculosis. Weight loss could mean cancer. Simply using a cough suppressant without proper treatment of the underlying problem can cause significant harm.

A coughing child who can eat,drink and play a little probably does not have a serious problem. Wheezing, barking cough, high fever or refusal to eat or drink, or cough with vomiting may be serious and warrants a physician's evaluation. Nighttime coughing alone may be asthma although children can have reflux. Persistent coughing, particularly in an infant, should prompt a call to the doctor. Although it might be croup that can often be successfully treated at home, it's a good idea to check with your doctor.

Next time you have a cough, before you reach for cough medicine, think what might be causing it and seek medical attention if there are significant associated symptoms or if a cough has lasted longer than three weeks. Remember that it may more difficult than you think to treat it.

(Media Contacts)

Last Updated March 19, 2009