My 15 year old daughter, 165 height, 65kg weight; on and off for the past 3 years has white puss like pimples with red surrounding, from her ankles to just above her knees. They start off really itching then begin to feel like bruises. They have been treated by doctors with acne pills but never seem to fully go away, and seem to flare up every few months. Could you help us on what these may be, what could be causing them and how to treat this.