Pediatr Nephrol. 2009 Jul 9; Coulthard MG, Verber I, Jani JC, Lawson GR, Stuart CA, Sharma V, Lamb WH, Keir MJThe aim of the study reported here was to determine whether kidney scarring after urinary tract infections (UTI) in children can be prevented and to identify the risk factors for developing scars. We identified children in the Northern health region of the UK who had been seen to develop scars, identified as new defects on dimercapto-succinic acid (DMSA) scanning. Risk factors were sought by reviewing case-notes and interviews with parents. Twenty girls were identified whose new scarring was strongly associated with having both vesicoureteric reflux (VUR) and a UTI (p = 0.0001); 19/23 (83%) of kidneys exposed to both of these factors developed scars. Children were much more likely to be febrile (94 vs. 30%, p < 0.0001) or unwell (82 vs. 10%, p < 0.0001) during their earlier UTIs when they were of median age 2.8 years (range 0.3-5.0 years) and did not scar, compared to their later UTIs at age 7.3 years (1.2-12.5 years), when they did scar. However, most patients were treated within 1 day of their symptoms for their early UTIs, compared to a wait >/=7 days for later UTIs (p = 0.001). Being febrile or unwell during a UTI does not predict the development of scars, but prompt treatment appears to prevent scarring in children with VUR.