What Can Cause Sudden Burst Of Shooting Pain And Bruising In Foot And Wrist?

I am a smoker but generally healthy person. Over the past couple months I have had four instances (2 in my left wrist and 1 in each foot) where I have a sudden burst of shooting pain and suddenly my foot or wrist is bruised. When I touch it, it feels and looks like it's an inflamed vein, but is extremely painful. Can someone please tell me what this could be?