The wheezing infant.

Wheeze is a symptom and not a diagnosis. It is extremely common in infancy; 20-30% of children have experienced recurrent episodic wheezing by the age of 12 months. Wheezing may result from widespread peripheral airway narrowing or, less commonly, from localized central disease. Excluding recurrent viral wheezing and asthma-like symptoms, all other specific causes of wheezing (e.g. cystic fibrosis, congenital airway disorders, chronic lung disease of prematurity) affect only 2-3% of the population. Although wheezing disease preceded by acute viral bronchiolitis early in infancy features prominently in most articles on childhood asthma, it affects, at most, 1% of the population. The increased prevalence of reported wheezing in industrialized countries until the mid-1990s, accompanied by an increase in the number of hospital admissions for wheezing, represents a true increase in the problem rather than simply increased awareness. In the UK, wheezing in pre-school children accounts for about 25% of acute hospital admissions in childhood, and almost 50% during epidemics of respiratory syncytial virus (RSV) infection.