SummaryIllnesses with wheezing in early infancy include a group of diseases with different pathogenesis and prognosis Early transient wheezing is associated with lower levels of lung function since birth and children usually become asymptomatic before the age of six years Infants with late onset wheezing usually become symptomatic during respiratory infections in preschool years The alteration of the airway tone control independent of atopy may play a role in the mechanism of late onset wheezing Persistant wheezing is associated with classical risk factors for asthma and the symptoms usually persist at the age of six Although at least 50 of children have wheezing in the first six years of life only a small percent of children develop asthma It is important to identify children at risk of developing asthma since early treatment of the disease prevent persistant airway damage A better understanding of the mechanisms of disease in these different wheezing phenotypes may lead to the development of more spesific treatments and preventive strategies Key words: Wheezing Phenotypes Asthma Prognosis

Illnesses with wheezing in early infancy include a group of diseases with different pathogenesis and prognosis Early transient wheezing is associated with lower levels of lung function since birth and children usually become asymptomatic before the age of six years Infants with late onset wheezing usually become symptomatic during respiratory infections in preschool years The alteration of the airway tone control independent of atopy may play a role in the mechanism of late onset wheezing Persistant wheezing is associated with classical risk factors for asthma and the symptoms usually persist at the age of six Although at least 50 of children have wheezing in the first six years of life only a small percent of children develop asthma It is important to identify children at risk of developing asthma since early treatment of the disease prevent persistant airway damage A better understanding of the mechanisms of disease in these different wheezing phenotypes may lead to the development of more spesific treatments and preventive strategies Key words: Wheezing Phenotypes Asthma Prognosis