Clinical study on cough variant asthma

Abstract

Chronic cough may be the sole presenting manifestation of bronchial asthma (reference 3; Corrao et al, 1979), and "cough variant asthma (CVA)" has been used to categorize such patients. In order to clarify the clinical picture of CVA, we evaluated the clinical history, laboratory data, sputum cytology and pulmonary function in 14 subjects (5 males and 9 females, aged 14 to 65 years) compatible with the following diagnostic criteria: (1) chronic cough persistent for more than 8 weeks, (2) no wheeze nor dyspnea, (3) no rales, (4) no past history of asthma, (5) bronchial hyperreactivity to methacholine proven by Takishima's method (reference 13), (6) effectiveness of bronchodilators against cough, (7) normal chest X-ray film, (8) afebrile and negative CRP, (9) absence of sinusitis and postnasal drip, or if present, they are proved not to be responsible for the cough, and (10) no other causes of cough such as heart disease, prescription of ACE inhibitors, current smoking. The results were as follows. 1) Many of the subjects were atopic, with positive skin tests to one or more common allergens in 10 subjects, elevated serum IgE in 4 subjects, and past history and family history of atopy in 4 and 7 subjects, respectively. 2) Respiratory infection preceded the onset of CVA in 3 subjects. 3) Cough was generally nocturnal, but 2 subjects coughed only in the daytime. 4) FEV1.0% was decreased (less than 70%) in only 2 subjects, whereas V25 was decreased (less than 80% of predicted value) in 11 out of 12 evaluable subjects, which suggested peripheral airway obstruction.(ABSTRACT TRUNCATED AT 250 WORDS)