what is the difference between Kaposi s Sarcoma that may be caused by HIV and normal falling abrasions? i have a strange abrasion on the front of my right leg, and i didn t notice it before it started to sting when my pants were rubbing against it 3 days ago, now it turned into this strange dark red color, it looks like a normal abrasion, the scab even came off when i went to shower, could this be KS? to my knowledge i am not HIV positive according to my last two ab/ag HIV tests (3 month and 2 years after my last possible encounter) and i had no other encounters since then, but every now and then i think maybe some body screwed something in the labs and i am going to end up being screwed my self! please clarify the difference between abrasions and KS