If I am allergic to certain sanitary pads (itchy, swollen, soreness around my thigh and pubic area), is it possible that the sanitary pads also cause certain allergic reactions inside the vagina and or even the wall of my womb? I am asking this question because I notice that when I switch between brands (on the very same day), the level of cramps and menstrual flow varies. I have experimented it deliberately and the results have been consistent. Could skin allergy to sanitary pads also caused allergy inside?