Chronic Cough Causes

By: Michael J. Flais, MD

Coughing is an important mechanism that helps to protect the lower airways and lungs from excessive secretions and foreign material. Chronic cough is defined as a cough that persists for more than eight weeks in adults, and more than 4 weeks in children. Chronic cough can be very frustrating and can greatly impact one’s quality of life. There are many potential causes for chronic cough, but the most common causes are postnasal drip, asthma, and GERD (gastroesophageal reflux disease). Some people with chronic cough have one of these conditions, two, or even all three.

Bacterial sinus infection, non-allergic rhinitis, and allergic rhinitis (hay fever) are the most common causes of postnasal drip. Symptoms of a sinus infection are typically sinus pain or pressure, and yellow or green nasal discharge. The symptoms of non-allergic rhinitis are similar to those of allergic rhinitis—runny nose, postnasal drip, and nasal congestion, but an allergy is not the cause. Weather changes, odors, eating, and even dry air can trigger symptoms of non-allergic rhinitis. We perform allergy skin testing, which can help to determine if nasal symptoms are due to an allergy or not.

Asthma symptoms are caused by inflammation in the lower airways. Most individuals with asthma experience difficulty breathing, wheezing and coughing. About 1/4 of asthma patients experience only coughing, and no shortness of breath or wheezing. Asthma is diagnosed based on a person’s pattern of shortness of breath, coughing, and/or wheezing, determining what triggers and what relieves those symptoms, and determining what other medical problems the person may have. We perform spirometry, a type of lung function test that can be helpful in diagnosing asthma.

Heartburn is the most common symptom of GERD. Some individuals with GERD also experience frequent belching, an acid or sour taste in the mouth, or abdominal discomfort. But some people have “silent GERD”, and don’t feel any of these symptoms. There are many ways in which acid can trigger coughing, oftentimes unbeknownst to the individual. Acid in the lower esophagus, which connects the mouth to the stomach, can trigger the esophageal-bronchial reflex. Acid can irritate the lower part of the throat (pharynx) or the upper part of the voice box (larynx). This is called LPR, or laryngopharyngeal reflux, which is a subtype of GERD. Also, acid can irritate the lower airways if one aspirates acid. In other words, the acid “goes down the wrong pipe”.

Allergists are specially trained to deal with chronic cough. If you or a loved one is experiencing a chronic cough call our offices today to schedule an appointment.

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