Introduction: Asthma, the most common chronic disease in paediatrics, is characterised by an inflammatory process involving the proximal and distal airways, with remodelling of the airways and changes in respiratory function.
State of the art: Recent studies in children have provided evidence of damage to the small airways identical to that occurring in adults. In fact inflammatory cells as well as structural alterations of the airways have been found in both bronchial biopsies and broncho-alveolar lavage fluid in infants and young children. At the functional level this damage is manifest by a reduction in maximum expiratory flow rates between 25-75% of the vital capacity. It also shows itself by the demonstration of thick walled bronchi and hypodense bands on the high resolution CT scan. It appears that conventional inhaled treatments have no effect on the small airways. Finally the main prognostic factors for this distal damage are respiratory infections and exposure to tobacco in utero.
Perspectives: Damage to the small airways in childhood asthma indicates the need for new therapies aimed at this part of the respiratory system.
Conclusion: Inflammation and remodelling of the small airways develops early in an asthmatic child whose respiratory system is growing rapidly and persists throughout life.