Talk to Gynecologist on Vaginal Itching During Period

I have been having irregular periods since the age of 13. This time I did have my period last month and it was followed by horrible vaginal itching which ended in 2.5 weeks. Now I again got my period yesterday, but the vaginal itching has again started today. I am changing my pads regularly (I use butterfly), I am properly cleaning myself and even using soap there but the itching seems to be there. Why is it that every time I manage to get my period, even after the irregular cycles, I face this itching? And what can I do to minimize it or stop it? Thank you.