||OBJECTIVE: To study the systemic activity of inhaled steroids in young children. METHODS: Forty children with mild asthma aged 1 to 3 years were studied in a 3-way crossover, randomized, placebo-controlled, double-blind trial. Treatment with inhaled fluticasone propionate, 200 microg twice daily delivered via pressurized metered-dose inhaler (pMDI) and Babyhaler (FP400), was compared with budesonide, 200 microg twice daily delivered via pMDI and NebuChamber (BUD400), and to placebo. The Babyhaler was primed before use. Knemometry was used to detect systemic steroid activity. It was performed with a hand-held knemometer after 1 and 4 weeks of treatment. The increase in lower-leg length within this 3-week period was used as the outcome measure. The intention-to-treat population was analyzed by analysis of variance. RESULTS: The increases in the lower-leg length during placebo, BUD400, and FP400 treatments were 85, 45, and 34 microm/d, respectively (adjusted mean). The growth in lower-leg length was significantly reduced from both steroid treatments. The difference between BUD400 and placebo was -40 microm/d (n = 25; 95% confidence interval [CI]: -8 to -72). The difference between FP400 and placebo was -51 microm/d (n = 26; 95% CI: -19 to -83). The difference between FP and BUD was -11 microm/d and was not statistically significant (n = 28; 95% CI: 20 to -42). CONCLUSION: FP and BUD are both systemically active in children 1 to 3 years old when administered for 4 weeks from their dedicated spacer devices in daily doses of 400 microg with no difference between the 2 steroid regimens. These findings call for studies of clinical side effects from these treatments of preschool children.