Hi, I'm A 22 Year Old Woman And Lately I

Hi, I'm a 22 year old woman and lately I have been experiencing itchy nipples, along with itchy feet. Three weeks ago I had unprotected sex and I got a std/sti test, they came back all clear. So it couldn't be anything from that area. Oh and also my nipples have been tingling too. What can I do to stop the itching and what is causing it? Thank you