Erythema nodosum

Last reviewed: 22 Feb 2023
Last updated: 30 Jul 2021



History and exam

Key diagnostic factors

  • presence of risk factors
  • nodules on shins
  • uveitis, red eyes, retinal nodules, or candle-wax drippings
  • nodules on other skin areas
  • anaesthetic skin lesions
More key diagnostic factors

Other diagnostic factors

  • joint pains
  • fever
  • diarrhoea, constipation, abdominal pain, haematochezia
  • enlarged spleen
  • miliary nodules on the retina
Other diagnostic factors

Risk factors

  • streptococcal infection
  • sarcoidosis
  • tuberculosis
  • coccidioidomycosis
  • histoplasmosis
  • blastomycosis
  • brucellosis
  • Behcet's disease
  • oral contraceptives
  • sulfonamides
  • iodides and anti-epileptic drugs
  • psittacosis
  • leprosy
  • inflammatory bowel disease
  • pregnancy
  • malignancy
More risk factors

Diagnostic investigations

1st investigations to order

  • FBC
  • anti-streptolysin-O titre
  • chest x-ray
  • tuberculin skin test, interferon gamma release assay
More 1st investigations to order

Investigations to consider

  • serum ACE level
  • skin lesion biopsy
  • coccidioidin skin test
  • histoplasmin skin test
  • lepromin skin test
  • blastomycosis serology
  • brucellosis serology
  • psittacosis serology
  • x-ray symptomatic joints
  • rheumatoid factor testing
  • Yersinia agglutination titre
  • Yersinia stool cultures
  • colonoscopy
  • serum IgD
  • deep punch biopsies including subcutaneous fat, or incisional biopsies
More investigations to consider

Treatment algorithm


mild to moderately severe symptoms

severe refractory symptoms



Daniela Kroshinsky, MD, MPH
Daniela Kroshinsky

Associate Professor of Dermatology

Harvard Medical School

Director of Pediatric Dermatology

Director of Inpatient Dermatology

Massachusetts General Hospital




DK declares that she has no competing interests.


Dr Daniela Kroshinsky would like to gratefully acknowledge Dr Om P. Sharma, a previous contributor to this topic. Dr Kroshinsky would also like to thank Priyanka Vedak for her contribution to this topic. We would like to gratefully acknowledge the contribution of the late Elisabeth Higgins (Consultant Dermatologist, King’s College Hospital) for her peer review of this topic.


OPS declared that he had no competing interests. PV declared that she had no competing interests. EH declared that she had no competing interests.

Peer reviewers

Robert T. Brodell, MD

Professor of Internal Medicine

Clinical Professor of Dermatopathology

Northeastern Ohio Universities College of Medicine


Associate Clinical Professor of Dermatology

Case Western Reserve University School of Medicine




RTB declares that he has no competing interests.

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