I HAD A SCALDED LOOKING ULCER THAT HURTS TO THE TOUCH,IT CAME BEFORE TO ME,i KNOW IT S NOT SYPHYLIS BECAUSE I DIDN T HAVE SEXUAL ACTIVITY WITH ANY BODY FOR YEARS,IT DOES NOT RESPOND TO sULFA DRUGS,TRIMETHOPRIM OR TO TOPICAL ANTIBIOTICS AS WELL,IT HEALS ON IT S OWN BUT IT LEAVES A DARKER PURPLE HUE AS TO WHERE IT WAS,I WONDER WHAT IS IT EXACTLY AND HOW TO PREVENT IT FROM HAPPENING AGAIN..?