Vaginal rash - six weeks ago - uti turned into kidney infection - now have the same rash again but much worse - can it be another uti and if so why?

Probably not: UTI does not cause rash in the vulva(I think you are referring to it as vagina). However, the antibiotic used for the UTI can give,as a side effect, a yeast infection in the vaginal area.If you are having no urinary symptoms,it is unlikely to be a UTI. You should be checked by your doctor or your gyn ,who will also check a urine sample and diagnose the rash. I hope this helps.