Asthma phenotypes: Wheezy infants and wheezy children

The relationship between wheezing illnesses in infancy and the development of asthma later in life has been the matter of considerable research and scientific interest for the last 50 years. Analysis of the different wheezing phenotypes in early life and of the relation between these phenotypes and the subsequent development of persistent asthma-like symptoms clearly indicate the complexity of the different forms of airway obstruction that may occur during childhood. This article reviews immune response to viruses and wheezing in infancy, the role of early allergies and of early allergic sensitization, transient, and infant wheezing.