What Causes Itchy Red Spots On The Knee?

I have itchy red spots on my left knee, right foot (top near toes) and bottom cheeks (both). My foot, bottom and knee also have a red ring that is fairly normal skin coloured inside it. My partner almost likens it to looking as though I have been bitten by a human. I have been using E45 cream but it's not helping. It's excruciatingly itchy so please help.....thanks.