Erythema Nodosum By Julia Benedetti, MD, Harvard Medical School Reviewed / Revised Apr 2022 | Modified Sep 2022 View Patient Education Etiology Symptoms and Signs Diagnosis Treatment Key Points Topic Resources Erythema Nodosum Erythema Nodosum (Leg) Erythema nodosum is a specific form of panniculitis characterized by tender, red or violet, palpable, subcutaneous nodules on the shins and occasionally other locations.