Episodic viral and multitrigger wheeze: different phenotypes or different diseases?
Episodic viral and multitrigger wheeze may reflect distinct disease processes in childhood.
The distinction between episodic viral wheeze (EVW) and multitrigger wheeze (MTW) is commonly used to guide management of preschool wheeze in clinical practice. However, the prognostic value of this classification is low. A recent study conducted on two birth cohorts evaluated the temporal stability of EVW and MTW at ages 2, 4 and 6 years. Children withEVW early remitted more frequently than children with MTW and children whose wheeze persisted over a 2-years period showed a tendency to remain in the same phenotype. The proportion of children with EVW decreased with age, whereas those of children with MTW increased. Besides, MTW was associated with more severe symptoms than MTW. The tendency to remain in the same phenotype was only partially explained by the severity of symptoms, suggesting that EVW and MTW may be distinct disease entities rather than different ends of a severity spectrum. Further studies are needed to understand the underlying differences between EVW and MTW and the associated risk factors. Moreover, a precise characterization of these two phenotypes will help in identifying the most effective treatments and in predicting each patient’s prognosis.