Episodic viral wheeze and multiple-trigger wheeze in preschool children are neither distinct nor constant patterns. A prospective multicenter cohort study in secondary care.

Objectives: To evaluate whether episodic viral wheeze (EVW) and multiple-trigger wheeze (MTW) are clinically distinguishable and stable preschool wheezing phenotypes.

Methods: Children of age 1 to 4 year with recurrent, pediatrician-confirmed wheeze were recruited from secondary care; 189 were included. Respiratory and viral upper respiratory tract infection (URTI) symptoms were recorded weekly by parents in an electronic diary during 12 months.