Preschool wheeze: phenotypes and beyond

Wheezing in preschool children is mostly associated with viral upper respiratory tract infections, can recur frequently and is not usually associated with any underlying inflammation between episodes of wheeze. While spontaneous resolution of wheezing occurs in some of these children, in others wheeze persists, and these children are at risk of developing asthma. A number of birth cohort studies have improved our understanding of the natural history of preschool wheeze disorders but many gaps in our knowledge still remain. This article summarizes existing knowledge regarding preschool wheeze phenotypes including clinical relevance, natural history of preschool wheeze disorders, pathophysiology and treatment strategies. This article will focus on preschool children with recurrent wheeze with or without viral respiratory tract infections.