Why Is My Vagina Itching So Badly

I have had severe vaginal itching - particularly my clitoris and vaginal lips. There is no odor, discharge, and there is only redness and swelling when I just can t take it and itch it like mad. I don t think it s a yeast infection or thrush since it sounds like those both require discharge, odor or sores - which I have none of. I noticed that it started one time after my husband and I had intercourse. seemed to go away when I would get my period. It is not going away now! I ve asked my husband and he has no itching or anything out of the ordinary going on with him. I am stumped! I already wear cotton underwear, have not switched detergents or tampons , have used vagisil to temporarily alleviate the itching. I don t use anything perfum-ey. what is it?