What Causes Vaginal Itching And Bad Odor Before Periods?

i have a vaginal itchy that ocurred few months ago, it's not persistant, but it occurs severly just few days before the menstrual cycle and few days after it...i can smeel a bad odour, there is no typical discharge, but i could find a white little discharge between labia minora and majora..there is no other symptoms (papules, vesicle...)