Chronic cough is defined as a cough lasting three to eight weeks in duration or longer. The most common cause of cough in nonsmokers with a normal chest x-ray include postnasal drip syndrome (PNDS), asthma, and gastroesophageal reflux disease (GERD). Other less common causes of cough include angiotensin converting enzyme inhibitor (ACEI) induced cough, postinfectious syndrome, tympanic membrane irritation, habit cough, and psychogenic cough.
Our thoughts on this problem mirror that which was published recently by the consensus panel of the American College of Chest Physicians (Chest 1998; 114(2)S133-S181). We have found that the treatment of PNDS has been most effective with a combination of inhaled corticosteroids given nasally and older generation antihistamine/decongestants such as dexbrompheniramine maleate (eg Bromphen 12 mg qd, Dehist 6 mg bid) and azatadine maleate (eg Optimine 1 mg bid). We have found that the newer nonsedating antihistamines are not effective for the treatment of PNDS. Ipratropium bromide given intranasally is also effective in some patients. When chronic sinusitis is suspected as the etiology of PNDS, radiographs should be obtained. Chronic sinusitis requires prolonged antibiotic therapy. Many patients with PNDS induced cough do not have classic findings on history and physical examination and require empiric treatment.
GERD may cause cough in completely asymptomatic patients. We treat patients empirically and do not often obtain diagnostic tests unless patients have been unresponsive to treatment. H-2 blockers, proton pump inhibitors, and motility agents are employed in the treatment of GERD. It should be noted that chronic cough secondary to GERD can take months to abate. The mean time to recovery has been calculated in studies to be between 161 to 179 days.
Patients with asthma may present with cough and shortness of breath. This type of presentation is known as cough equivalent asthma. In patients with normal spirometry, we often obtain methacholine challenge testing (MCT). Standard treatment for asthma improves the patients symptoms and results in elimination of the cough.
When trying to get the specific cause of the patient’s cough under control, antitussive agents are often necessary to provide the patient with relief from a chronic nagging cough.