Extreme vaginal itch. no pain. started a month ago. begins before each period, clears up completely shortly after. also strange odor. worse during day?

Could be BV: BV or bacterial vaginosis is a common vaginal infection. It can cause odor and also itching & discharge. When you have you period, the pH of the vagina can change leading to an overgrowth of bacteria. Don't douche. Also, the sanitary napkin or tampon you are using might be causing a dermatitis and making you feel itchy. Have your GYN evaluate to differentiate & help guide you.