Chronic cough is defined as a cough lasting for more than six weeks. The acute causes of cough such as upper respiratory infections should not persist beyond six weeks. There are three major causes of chronic cough: asthma, gastro-esophageal reflux disease (GERD) and postnasal drip syndrome. More than one risk factor can be present at the same time. Occasionally, medications can cause chronic cough, such as ACE-inhibitors, which are used to treat hypertension.
There are two approaches to the management of chronic cough. If a patient's history strongly suggests a specific cause for the cough, then standard “first-line” treatment is usually tried for 6-12 weeks. Often, the cough has been present for years and multiple therapies have already been tried. Under these circumstances, diagnostic testing is another option. This involves a variety of tests to identify or exclude the most common causes of chronic cough.
If initial breathing tests do not suggest asthma then a methacholine challenge (bronchoprovocation) may be performed. This test can identify cough-variant asthma. If the methacholine challenge is negative, then asthma can be eliminated as a cause of the cough. GERD testing includes 24-hour pH monitoring and manometry. If these tests are normal, GERD is not a contributing cause. If these tests are positive, it would suggest, but does not definitively prove that GERD is causing the cough. Postnasal drip syndrome has no specific diagnostic test.
Treatment depends on the suspected cause and the test results. Asthma is treated with inhaled steroids and bronchodilators. GERD is treated with high dose proton pump inhibitors and strict dietary modification to eliminate caffeine, citrus, alcohol and spicy food. Antihistamines are the treatment of choice for postnasal drip syndrome.
Additional testing may be appropriate in more complex cases. These tests include computed tomography (CT) of the chest, bronchoscopy, polysomnography, and ENT evaluation. The treatment of chronic cough is a slow process. Patients are often frustrated by the slow pace of progress.
The lung doctors at Arizona Pulmonary Specialists are experts in diagnosing and treating chronic cough. Our team of doctors, nurses and respiratory therapists will work with you to ensure that you understand your medicines and other treatments.