Two days ago I was having pain around my knee. I have lupus so I didn t think much of it. The next day I notice a large purple bruise behind my knee. That bruisIng is now traveling down my leg and is even in my ankle. On day two I also started feeling pain on the inside of my upper thigh on the opposite leg.
Hello, A large purple bruise without any history of injury can happen due to a low platelet count or a fragile skin caused by a regular steroid intake. You need to get your bleeding and clotting profile evaluated.  Hope I have answered your query. Let me know if I can assist you further. Take care Chat Doctor.