Cough variant asthma is associated with a higher wheezing threshold than classic asthma
- 1 August 1993
- journal article
- Published by Wiley in Clinical and Experimental Allergy
- Vol. 23 (8), 696-701
- https://doi.org/10.1111/j.1365-2222.1993.tb01796.x
Abstract
Cough variant asthma is an occult form of asthma in which the only sign or symptom is chronic cough. It is a common problem amongst all ages that frequently goes unrecognized, leading to underdiagnosis and undertreatment. To characterize the pathophysiological abnormalities in these patients, we performed bronchial provocation tests with methacholine using the stepwise doubling concentration technique, and measured the concentration of methacholine and the severity of airway obstruction when wheezing was first detected. Airway hyperresponsiveness, defined as PC20 in the cough variant asthma group was not significantly different from that of classic asthma. There was a good correlation between the PCW (the concentration of methacholine causing wheezing) and the PC20 with the PCW values higher than PC20 values in both groups. However, in the cough variant asthma group, the PCW:PC20 ratio was greater than that of the classic asthma group. Furthermore, the mean % fall in FEV1 at which wheezing was first detected in the former group was significantly larger than that of the latter group. The results indicated that the mechanism for the manifestation of cough without wheeze in the cough variant asthma may be a higher wheezing threshold, i.e. wheezing becomes audible at the greater degree of airway obstruction than classic asthma. They suggested that patients with cough variant asthma may represent a subset of asthmatic subjects whose airways are less able to produce a wheeze.Keywords
This publication has 27 references indexed in Scilit:
- Delay in diagnosis of childhood asthma and its influence on respiratory consultation rates.Archives of Disease in Childhood, 1991
- Cough Variant Asthma: A Review of the Clinical LiteratureJournal of Asthma, 1991
- A Portable System for the Spectral Analysis of Cough Sounds in AsthmaJournal of Asthma, 1990
- Chronic cough in childhood: Approach to diagnosis and treatmentThe Journal of Pediatrics, 1989
- Bronchial provocation tests in young children using tracheal auscultationThe Journal of Pediatrics, 1988
- Prevalence of asthma and hay fever in England and Wales.BMJ, 1987
- Night cough counts and diary card scores in asthma.Archives of Disease in Childhood, 1985
- Prevalence and spectrum of asthma in childhood.BMJ, 1983
- Chronic Cough as the Sole Presenting Manifestation of Bronchial AsthmaNew England Journal of Medicine, 1979
- Bronchial reactivity to inhaled histamine: a method and clinical surveyClinical and Experimental Allergy, 1977