Urinary tract infection (UTI) is the most frequently occurring serious bacterial infection in young children and accounts 5 to 14% of emergency department visits Formation of renal scarring in children has been associated with serious complications as hypertension, preeclampsia, and end stage renal failure in young age . So, this study aims to determine whether dexamethasone reduces the renal scarring in children will be treated with antibiotics for acute pyelonephritis. investigators propose to conduct a multi center, randomized, placebo-controlled, double-blind clinical trial, that will evaluate the efficacy of dexamethasone (0.3 mg/kg every 12 hours per day orally for 3 days) in preventing renal scarring in young febrile children (2 months to 14 years) with a first-diagnosed UTI. 120 Participants will be enrolled over a 3-year period from 6 sites.