How To Remove Itchy Red Spots On Both Legs?

I have red spots on my both legs around the knee areas. Those spots are extremely itchy so when I scratch my legs they bocome bruised easily. I went to my family doctor, got medicated cream and after 3 weeks is not working. I visited dermatologist, got Vibramycin and medicated gel to put on my rash. It's still not going away.What is wrong and what it could be? I never had this things before