Skin-nontumor / Clinical dermatology
Other dermatoses
Erythema nodosum

Author: Mowafak Hamodat, M.D., MB.CH.B, MSc., FRCPC (see Authors page)

Revised: 24 June 2016, last major update July 2011

Copyright: (c) 2002-2016, PathologyOutlines.com, Inc.

PubMed Search: Erythema nodosum [title] skin

Cite this page: Erythema nodosum. PathologyOutlines.com website. http://pathologyoutlines.com/topic/skinnontumorerythemanodosum.html. Accessed December 7th, 2016.
Definition / General
  • Panniculitis with tender red nodules, usually on both shins
Terminology
  • Erythema nodosum migrans (subacute nodular migratory panniculitis, migratory panniculitis): asymmetrical, unilateral, and distributed solely on the legs; marked female predominance; older age group
  • Chronic erythema nodosum: nodules appear over months/years; otherwise indistinguishable from typical condition
Clinical Features
  • Red, painful, bilateral, symmetrical nodules, elevated above the skin surface
  • On anterior surface of legs, arms, face, calves and trunk
  • Usually involutes in days/weeks, leaving depressed, pigmented lesions
  • No ulceration
  • Immune mediated, but precise mechanism is unknown
  • May be associated with streptococcus infection, tuberculosis, sarcoidosis, coccidioidomycosis, ulcerative colitis, Behcet’s disease, drug reactions or idiopathic; also Hodgkin lymphoma, renal cell carcinoma and carcinomas of colon, pancreas and uterine cervix
Clinical Images

Images hosted on other servers:

Various images

Micro Description
  • A prototype of septal panniculitis, characterized by vascular changes, septal inflammation, hemorrhage and variable acute and chronic panniculitis
  • Both septal and lobular panniculitis
  • Marked septal fibrosis, infiltrated by lymphocytes, neutrophils, histiocytes and granulomas with giant cells
  • Septal infiltrate spills over to affect the fat lobules
  • Dermis shows perivascular and periadnexal chronic inflammatory cell infiltrate
  • Early, the septal inflammation is acute and characterized by neutrophils, soon replaced by lymphocytes and histiocytes
  • Variable eosinophils, variable vasculitis

  • Miescher’s radial granuloma: characteristic finding of erythema nodosum; septal collection of histiocytes surrounding a cleft (appear to look like spaces); reported in Sweet’s syndrome, nodular vasculitis and necrobiotic lipodica
Micro Images

Images hosted on other servers:

Septal panniculitis and Miescher's granulomata

Differential Diagnosis
  • Nodular vasculitis or subacute nodular migratory panniculitis: usually septal
  • Weber-Christian disease associated panniculitis: usually lobular inflammation