TYPES OF ASTHMA AND WHEEZING

There is now convincing evidence that childhood asthma is a spectrum o f different conditions that are manifested by recurrent symptoms of br onchial obstruction. Risk factors such as age, genetic background, deg ree of maturation at birth and allergic sensitization, amongst others, are important in determining asthma-like manifestations at different times during childhood. Although efforts have been made to differentia te ''wheezing syndromes'' occurring during childhood, these efforts ha ve been made more difficult by the significant degree of overlap betwe en them. Nevertheless, the evidence suggests that recurrent obstructiv e symptoms remit in a large number of children who develop these sympt oms during the first 3 yrs of life, and low lung function seems to be the main risk factor for these transient episodes. On the other hand, children who will go on to develop persistent wheezing beyond infancy and early childhood usually have a family history of asthma and allerg ies and present with allergic symptoms very early in life, Recent stud ies suggest that the latter also show acute immune responses to viruse s that are different from those of transient wheezers. Identification of specific inflammatory markers for persistent wheezing at the time o f the first lower respiratory symptoms may be a necessary step for the establishment of successful strategies for the prevention of asthma i n the future.