Diurnal Variation Children with of Peak Expiratory Flow in Cough Variant Asthma

Cough variant asthma (CVA) is thought to be a variant form of asthma in which cough is the sole clinical manifestation of airways hyperresponsiveness, a characteristic feature of asthma. Another characteristic feature of asthma includes an increased diurnal variation of peak expiratory flow (PEF) compared to normal subjects. To examine whether diurnal variation of PEF might also increase in children with CVA, we have examined the degree of diurnal variation of PEF in these children (n = 7) by measuring peak flow serially for a week, and cornpared it with those in mild to moderate asthma (n = 17) and in control children without cough (n = 8). In control children without cough, the average value of the mean diurnal variation of PEF was 10.4 k 0.8%. In both groups of children with asthma and with CVA, there was a significant increase in the value (20.5 k 1.3% and 23.6 k 3.6%, respectively) compared to that in control children (p < 0.01 in both groups), although there was no significant dif