About 4 Months Ago I Noticed My Outer Thigh Was

About 4 months ago I noticed my outer thigh was horribly itchy with a burning sensation. I then noticed the area (about 4 inches long and 3 inches wide) was red and hot to the touch. Within an hour or 2 the itching subsided and the area turned into a sore bruise. I feared it was a blood clot and went to the emergency room. The doctor did not perform any diagnostic tests and told me I must have hit my leg and not noticed. Today I noticed the exact same burning itch in the exact same area. Again, the area was hot and red, here I am 2 hours later and it is a bruise again. What could this be? I am very concerned!