Rash On Leg (On My Left Shin)

About 2 months ago, I noticed a rash on my left leg, more specifically on my shin.  The rash covers an area of approximately 4 inches by 3 inches.  I do not know what caused the rash.  There are times when it becomes very itchy, it is not tender to touch, and it does not cause me any pain.  I have not tried putting any medication on it.  I figured it would eventually just go away, but now it's been a while and I'm not sure what to do.  I have attached two photos for your review.  Any help would be greatly appreciated, thank you in advance.