If you dont have TB , RA, Lupus , or Sarcodisis, and none of the known meds that cause it, what are some of the other Conditions that cause Erythmea Nodosum because my dr.s seem to be stumped but their frustration has not tested for everything and it sure hasnt helped me. Also I have a come and go pain in the right back side of my head 3 1/2 inches behind my ear. Any ideas?