Although dyspnea is the most common and distressing symptom in patients with chronic interstitial lung disease, chronic cough, a potentially debilitating symptom that impairs health-related quality of life, has been described as another common symptom in these patients.
Many patients with interstitial lung disease have their chronic cough mistakenly attributed to that condition when, in fact, the cough is due to more common disorders such as asthma, upper airway cough syndrome (previously referred to as postnasal drip syndrome), or gastroesophageal reflux disease. This article presents new data on a select group of patients and shows that more than 50% of patients with interstitial lung disease who are referred to a cough clinic for evaluation can have cough caused by these other more common causes of chronic cough. It is also clear, however, that chronic interstitial lung disease, by itself, can cause chronic cough, perhaps related to an increased cough reflex sensitivity.
Clinicians should be cautious when ascribing chronic cough to interstitial lung disease without first completely evaluating for other possible causes of cough. When cough is attributed to interstitial lung disease, therapy, when available, should be directed at the specific underlying diagnosis. Corticosteroids may be helpful in alleviating chronic cough in some cases of interstitial lung disease, but, because of the potential side effects of corticosteroids and lack of proven efficacy for some types of interstitial lung disease (e.g. idiopathic pulmonary fibrosis), treatment should weigh the risks and benefits for each patient individually. Nonspecific antitussive therapies shown to be clinically effective for chronic cough in general are codeine and dextromethorphan, but these have not been studied specifically in interstitial lung disease.
Division of Pulmonary, Allergy and Critical Care Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, USA
Correspondence to J. Mark Madison, Department of Medicine, LRB 319, UMass Medical School, 364 Plantation Street, Worcester, MA 01605-2324, USA
Tel: 508 856 6938; fax: 508 856 3999; e-mail: Mark.Madison@umassmed.edu