Medscape is available in 5 Language Editions – Choose your Edition here.


Erythema Nodosum

  • Author: Jeanette L Hebel, MD; Chief Editor: William D James, MD  more...
Updated: Mar 03, 2016


Erythema nodosum (EN) is an acute, nodular, erythematous eruption that usually is limited to the extensor aspects of the lower legs. Chronic or recurrent erythema nodosum is rare but may occur. Erythema nodosum is presumed to be a hypersensitivity reaction and may occur in association with several systemic diseases or drug therapies, or it may be idiopathic. The inflammatory reaction occurs in the panniculus.



Erythema nodosum probably is a delayed hypersensitivity reaction to a variety of antigens; circulating immune complexes have not been found in idiopathic or uncomplicated cases but may be demonstrated in patients with inflammatory bowel disease.[1]




United States

Peak incidence occurs at age 18-34 years. Age and sex distributions vary according to etiology and geographic location.[2]


Rates of erythema nodosum vary according to country. In England, the rate is 2.4 cases per 10,000 per year.


Women are affected more often than men, with a male-to-female ratio of 1:4.


Erythema nodosum may occur in children and in patients older than 70 years, but it is more common in young adults aged 18-34 years. Age distribution varies with geographic location and etiology.

Contributor Information and Disclosures

Jeanette L Hebel, MD Dermatologist, Dermatology Associates of Lancaster; Dermatologist, Department of Dermatology, Lancaster General Hospital

Jeanette L Hebel, MD is a member of the following medical societies: American Academy of Dermatology, American College of Mohs Surgery

Disclosure: Nothing to disclose.

Specialty Editor Board

David F Butler, MD Section Chief of Dermatology, Central Texas Veterans Healthcare System; Professor of Dermatology, Texas A&M University College of Medicine; Founding Chair, Department of Dermatology, Scott and White Clinic

David F Butler, MD is a member of the following medical societies: American Medical Association, Alpha Omega Alpha, Association of Military Dermatologists, American Academy of Dermatology, American Society for Dermatologic Surgery, American Society for MOHS Surgery, Phi Beta Kappa

Disclosure: Nothing to disclose.

Edward F Chan, MD Clinical Assistant Professor, Department of Dermatology, University of Pennsylvania School of Medicine

Edward F Chan, MD is a member of the following medical societies: American Academy of Dermatology, American Society of Dermatopathology, Society for Investigative Dermatology

Disclosure: Nothing to disclose.

Chief Editor

William D James, MD Paul R Gross Professor of Dermatology, Vice-Chairman, Residency Program Director, Department of Dermatology, University of Pennsylvania School of Medicine

William D James, MD is a member of the following medical societies: American Academy of Dermatology, Society for Investigative Dermatology

Disclosure: Nothing to disclose.

Additional Contributors

Timothy McCalmont, MD Director, UCSF Dermatopathology Service, Professor of Clinical Pathology and Dermatology, Departments of Pathology and Dermatology, University of California at San Francisco; Editor-in-Chief, Journal of Cutaneous Pathology

Timothy McCalmont, MD is a member of the following medical societies: Alpha Omega Alpha, American Medical Association, American Society of Dermatopathology, California Medical Association, College of American Pathologists, United States and Canadian Academy of Pathology

Disclosure: Received consulting fee from Apsara for independent contractor.


Thomas Habif, MD Adjunct Professor, Department of Internal Medicine, Section of Dermatology, Dartmouth Medical School

Thomas Habif, MD is a member of the following medical societies: American Academy of Dermatology and New Hampshire Medical Society

Disclosure: Nothing to disclose.

  1. Nguyen GC, Torres EA, Regueiro M, et al. Inflammatory bowel disease characteristics among African Americans, Hispanics, and non-Hispanic Whites: characterization of a large North American cohort. Am J Gastroenterol. 2006 May. 101(5):1012-23. [Medline].

  2. Mert A, Ozaras R, Tabak F, Pekmezci S, Demirkesen C, Ozturk R. Erythema nodosum: an experience of 10 years. Scand J Infect Dis. 2004. 36(6-7):424-7. [Medline].

  3. Psychos DN, Voulgari PV, Skopouli FN, Drosos AA, Moutsopoulos HM. Erythema nodosum: the underlying conditions. Clin Rheumatol. 2000. 19(3):212-6. [Medline].

  4. Mert A, Ozaras R, Tabak F, Ozturk R. Primary tuberculosis cases presenting with erythema nodosum. J Dermatol. 2004 Jan. 31(1):66-8. [Medline].

  5. Kakourou T, Drosatou P, Psychou F, Aroni K, Nicolaidou P. Erythema nodosum in children: a prospective study. J Am Acad Dermatol. 2001 Jan. 44(1):17-21. [Medline].

  6. Requena L, Yus ES. Erythema nodosum. Dermatol Clin. 2008 Oct. 26(4):425-38, v. [Medline].

  7. Bottone EJ. Yersinia enterocolitica: the charisma continues. Clin Microbiol Rev. 1997 Apr. 10(2):257-76. [Medline].

  8. Polcari IC, Stein SL. Panniculitis in childhood. Dermatol Ther. 2010 Jul-Aug. 23(4):356-67. [Medline].

  9. García-Porrúa C, González-Gay MA, Vázquez-Caruncho M, López-Lazaro L, Lueiro M, Fernández ML, et al. Erythema nodosum: etiologic and predictive factors in a defined population. Arthritis Rheum. 2000 Mar. 43(3):584-92. [Medline].

  10. Farhi D, Cosnes J, Zizi N, et al. Significance of erythema nodosum and pyoderma gangrenosum in inflammatory bowel diseases: a cohort study of 2402 patients. Medicine (Baltimore). 2008 Sep. 87(5):281-93. [Medline].

  11. Sullivan R, Clowers-Webb H, Davis MD. Erythema nodosum: a presenting sign of acute myelogenous leukemia. Cutis. 2005 Aug. 76(2):114-6. [Medline].

  12. Wanat KA, Rosenbach M. Cutaneous Sarcoidosis. Clin Chest Med. 2015 Dec. 36 (4):685-702. [Medline].

  13. Grunewald J, Eklund A. Lofgren's syndrome: human leukocyte antigen strongly influences the disease course. Am J Respir Crit Care Med. 2009 Feb 15. 179(4):307-12. [Medline].

  14. Moraes AJ, Soares PM, Zapata AL, Lotito AP, Sallum AM, Silva CA. Panniculitis in childhood and adolescence. Pediatr Int. 2006 Feb. 48(1):48-53. [Medline].

  15. Requena L, Yus ES. Panniculitis. Part I. Mostly septal panniculitis. J Am Acad Dermatol. 2001 Aug. 45(2):163-83; quiz 184-6. [Medline].

  16. Sterling JB, Heymann WR. Potassium iodide in dermatology: a 19th century drug for the 21st century-uses, pharmacology, adverse effects, and contraindications. J Am Acad Dermatol. 2000 Oct. 43(4):691-7. [Medline].

  17. Gilchrist H, Patterson JW. Erythema nodosum and erythema induratum (nodular vasculitis): diagnosis and management. Dermatol Ther. 2010 Jul-Aug. 23(4):320-7. [Medline].

Classic presentation of erythema nodosum with nodular red swellings over the shins.
All material on this website is protected by copyright, Copyright © 1994-2016 by WebMD LLC. This website also contains material copyrighted by 3rd parties.