I just found out 2 weeks ago I have this condition. My kidney and GI specialists both said it was arthritis related. After looking it up on the internet everything I have points to erythema nodosum. Mine have turned in to bruise like places. Still sore to touch. Have been on prednisone for years because of polymialgia and RA. Hopefully this is just one episode only. I’m 72 years old and in good health otherwise.