CHRONIC COUGH AS THE SOLE PRESENTING MANIFESTATION OF BRONCHIAL-ASTHMA

Six patients with chronic cough, without history of dyspnea or wheezing, had normal base-line spirometry but hyper-reactive airways, as demonstrated with methacholine. Maintenance therapy with bronchodilators promptly eliminated the cough in all patients. Three to 12 months later therapy was discontinued for three days, cough returned, and detailed pulmonary-function studies were carried out. Again, base-line values were normal, but after methacholine one-second forced expiratory volume decreased an average of 40 per cent in the patients as compared to 3 per cent in normal controls (P<0.001). The point of identical flow was increased by methacholine to 43.5 per cent of vital capacity in the patients, as compared to 6 per cent in normal controls (P<0.001), and the alveolar plateau was 4.8 ΔN2 per liter, as compared to 1.4 in normal controls (P<0.01). Specific airway conductance was lowered in patients and controls, but the post-methacholine value was significantly lower in the patients. On the basis of their persistently hyper-reactive airways, inducible diffuse airway bronchoconstriction and excellent response to bronchodilator therapy, these patients appear to have a variant form of asthma in which the only presenting symptom is cough. (N Engl J Med 300:633–637, 1979) COUGH is commonly associated with episodic wheezing and dyspnea in symptomatic asthmatic patients. Although wheezing is generally considered to be the sine qua non of bronchial asthma, McFadden has reported on patients who complained only of cough.1 The diagnosis of asthma was suggested by a history of episodic wheezing and confirmed by the demonstration of reversible airways obstruction by spirometry. The purpose of this paper is to report on six patients with chronic persistent cough who, when challenged with a cholinergic agent, methacholine, had hyper-reactive airways characteristic of asthma. However, unlike the patients described by McFadden, none of these six. © 1979, Massachusetts Medical Society. All rights reserved.