Factors that affect the efficacy of inhaled corticosteroids for infants and young children

Data obtained from studies of adults should not be extrapolated to children without careful consideration, particularly to infants and children less than 3 to 4 years of age. Infants and young children have narrower URT and LRT airways and a greater inspiratory flow velocity, resulting in greater upper and central LRT aerosol deposition compared with adults. This is especially true for children younger than 18 months, who are obligate nose breathers.