Wheezing Phenotypes in Preschoolers

The incidence of wheezing is very high during the first years of life. Up to 25-30% of the infants have at least one episode of wheezing. The diagnostic approache should start with the differentiation between congenital or inherited wheezing, and subsequently the diagnosis of acute, chronic or recurrent wheezing (RW). In children with RW or chronic wheezing the somatic development is relevant. If the child presents a good nutritional status and a good general state, the most frequent diagnosis would be asthma. In children with failure to thrive the investigation plan will start with cystic fibrosis and gastroesophageal reflux. There are two major classification of RW in children: according to symptoms and to the clinical course. Wheezing phenotypes based on symptoms are: 1) episodic wheezing, in which the duration of symptoms is short, without any symptoms between episodes, and they associate other sings of viral infection; and 2) wheezing with multiple triggers (beside infections they present wheezing during exercise, or after allergen exposure, or during emotional changes). According to clinical course there are three main RW phenotypes: 1) transient wheezing with early onset, during infancy; 2) persistent wheezing with the onset during the first 3 years of life and persistence of symptoms after 6 years, and 3) RW with late onset, after the age of 3 years. The last two may be related to atopy. In these children we use the Asthma Predictive Index (API) to identify the future patients with asthma that require lonf term therapy.