Why are infants prone to wheeze? Physiological aspects of wheezing disorders in infants.

Wheezing in infants is common and increasing in prevalence. Infants are particularly prone to wheezing due to developmental differences in airway mechanics compared to adults. These effects are enhanced in the presence of airway inflammation. Wheezing in infants is related to flow limitation which is a function of airway calibre and airway wall compliance. This review discusses the factors contributing to flow limitation and hence, wheezing. It tries to make the link between risk factors influencing airway structure, and thus function, with particular emphasis on the special physiological peculiarities of infants and lung growth. While in adults inflammation and remodelling alone may explain structural and functional changes in wheezing disorders, this reviews proposes a model emphasising that in infants inflammation, remodelling and airway development have to be considered as a continuously interacting system.