Chapter 11: the infant and toddler with wheezing.
AuthorsRobison RG, et al. Show all Journal
Allergy Asthma Proc. 2012 May-Jun;33 Suppl 1:S36-8. doi: 10.2500/aap.2012.33
.3543.
Affiliation
Division of Allergy-Immunology, Department of Medicine, Northwestern
University Feinberg School of Medicine, Chicago, Illinois, USA.
Abstract
Recurrent wheezing is common in young infants and toddlers with 27% of all
children having at least one wheezing episode by the age of 9 years. The
initial wheezing episodes in young children often are linked to respiratory
infections due to viral pathogens such as respiratory syncytial virus,
rhinovirus, human metapneumovirus, and influenza virus. Bacterial
colonization of the neonatal airway also may be significant in the late
development of recurrent wheeze and asthma. Some 60% of children who wheeze
in the first 3 years of life will have resolution of wheezing by age 6 years
("transient early wheezers"). Children who are "transient early wheezers"
have reduced lung function, which remains low at age 6 years, although
wheezing has ceased when compared with children who have never wheezed. In
contrast, "nonatopic wheezers" represent 20% of wheezing toddlers <3 years
of age. These children have more frequent symptoms during the 1st year of
life and may continue to wheeze through childhood, but, typically, episodes
become less frequent by early adolescence. Lung function in "nonatopic
wheezers" is slightly lower than in control subjects from birth to 11 years
of age, but they do not have bronchial hyperreactivity on methacholine
challenge. The third phenotype refers to "atopic wheezing" or wheezing
associated with IgE sensitization. This phenotype accounts for the last 20%
of wheezing children <3 years of age. These "atopic wheezers" have normal
lung function in infancy; however, lung function is reduced by age 6 years
and bronchial hyperreactivity typically is observed.
