Recurrent urinary tract infection (UTI) in adults is defined as repeated UTI with a frequency of 2 or more UTIs in the last 6 months or 3 or more UTIs in the last 12 months (European Association of Urology [EAU] guidelines on urological infections ).
Recurrent UTI is diagnosed in children and young people under 16 years if they have:
2 or more episodes of UTI with acute pyelonephritis/upper UTI or
1 episode of UTI with acute pyelonephritis plus 1 or more episode of UTI with cystitis/lower UTI or
3 or more episodes of UTI with cystitis/lower UTI.
See the NICE guideline on urinary tract infection in under 16s.