Chronic cough due to asthma: ACCP evidence-based clinical practice guidelines.

BACKGROUND: Asthma is among the most common causes of chronic cough in adult nonsmokers. Although cough usually accompanies dyspnea and wheezing, it may present in isolation as a precursor of typical asthmatic symptoms, or it may remain the predominant or sole symptom of asthma. The latter condition is known as cough-variant asthma (CVA).
METHODS: Data for this review were obtained from a National Library of Medicine (PubMed) search, performed in April 2004, of the English language literature from 1975 to 2004, limited to human studies, using the search terms "cough" and "asthma."
RESULTS: The diagnosis of cough not associated with typical asthmatic symptoms (ie, CVA) presents a challenge, because physical examination and spirometry findings may be entirely normal. Methacholine inhalation challenge testing can demonstrate the presence of bronchial hyperresponsiveness; however, the diagnosis of cough due to asthma is only confirmed after the resolution of cough with antiasthmatic therapy. In general, the therapeutic approach to asthmatic cough is similar to that of the typical form of asthma. Most patients will respond to inhaled bronchodilators and inhaled corticosteroids. A subgroup of patients will require the addition of leukotriene receptor antagonists and/or a short course of oral corticosteroids.
CONCLUSIONS: Asthma should be considered as a potential etiology in any patient with chronic cough, because asthma is a common condition that is commonly associated with cough. Because the subgroup of asthmatic patients with CVA presents with no other symptoms of asthma, clinical suspicion must remain high. Cough due to asthma responds to standard antiasthmatic therapy.