ABSTRACT
The past decade has witnessed significant advances in our understanding of the epidemiology of wheezing illnesses occurring during the first years of life. Several longitudinal studies initiated either during pregnancy or at birth, and in which follow-up has been extended beyond the preschool years, have provided a new perspective on the risk factors for and prognosis of these illnesses. There is now clear evidence indicating that wheezing in early life is a heterogeneous condition, in which recurrent episodes of airway obstruction are the final common pathway for the expression of different underlying mechanisms and, ultimately, for different diseases. This marked heterogeneity may explain the difficulty that most clinicians encounter in treating these illnesses which appear to be less responsive to the usually successful treatment prescribed to older children and adults with asthma (see Chapter 7). There are also ‘atypical’ forms of noisy breathing in this age group that contribute to the complexity of their diagnosis and treatment (see Chapter 4). However, even when confronted with the typical presentation of this condition the pediatrician is often unable to predict the response to therapy and to answer the most pressing question of parents, ‘Does my child have asthma?’. In this review of the epidemiology of wheezing diseases in early life an attempt will be made to provide a logical basis to explain the nature of the problem.
