My 3 year old son developed red spots around his knees yesterday and then a 103 fever . The fever has subsided today but the spots have spread to other joint areas, groin , elbows, wrists. These spots quite large, about the size of a pencil eraser up to a dime, are flat and some have a white spot in the center. He has been vacinated for chickenpox and doesn t compain of itching. Any ideas? Thanks.