Wheezing phenotypes
- Dr L I Landau, The University of Western Australia, Crawley, WA 6009, Australia; llandau{at}meddent.uwa.edu.au
There are increasing reports of excellent data on wheezing phenotypes in early childhood.1 Despite some contradictory findings, generally based on differences in definitions used or ages studied, the findings are gradually providing valuable perspectives towards understanding this very common symptom. It is clear that much of respiratory disease throughout life is programmed during fetal life and the early years after birth. The patterns differ between developing and developed countries, apparently related to differences in microbial exposure, diet and exposure to cigarette smoke.2 3 The outcomes are probably mediated through the effects of these agents, timing of these exposures being critical, on airway development and maturation of the immune system.4 The airways may be structurally smaller due to abnormalities of the wall size, function of the smooth muscle or increased thickness of the mucosa. Abnormal maturation of the immune system influences the response to both allergens and microbes promoting either hypersensitivity or tolerance.5
Cough and wheeze are very common symptoms in the early years of life with more than 60% coughing and more than 30% wheezing in the first year.6 Wheeze is a cardinal symptom of asthma but, in the first year of life, more than half is …
