Table 1.

Characteristics of episodic viral wheeze and of multiple trigger wheeze.

	Episodic viral wheeze	Multiple trigger wheeze
Definition	Wheezing during discrete time periods, often in association with clinical evidence of a viral cold	Wheezing that shows discrete exacerbations but also symptoms between episodes
Triggers	Viral infections	Viral infections, tobacco smoke, allergen exposure, mist exposure, crying, and exercise
Possible underlying factors	Preexistent impaired lung function, tobacco smoke exposure, prematurity, and atopy	Eosinophilic inflammation?
Continuing treatment with ICS	Little or no benefit	Significant fewer days with symptoms
Treatment with montelukast	Moderate benefit	Moderate reduction in exacerbations
Long-term outcome	Declines over time (<6 yrs) may continue into school age as episodic viral wheeze and may change into multiple trigger wheeze	May continue into adulthood as asthma