Chronic erythema nodosum

Erythema nodosum
Classification and external resources
10 9 DiseasesDB MedlinePlus eMedicine MeSH D004893

Erythema nodosum (EN) is an inflammatory condition characterised by inflammation of the fat cells under the skin characterized by tender red nodules or lumps that are usually seen on both shins. It can be caused be a variety of conditions, and typically resolves spontaneously within 3–6 weeks.

Signs and symptoms

Erythema nodosum is characterised by red nodules that are tender and warm. [1] Nodules occur under the skin, classically in front of the shins. Nodules may occur anywhere there is fat under the skin, including the thighs, arms, trunk, face, and neck. [1]

Erythema nodosum may occur concurrently with fever, malaise, and joint pain and inflammation. [1] Nodules may vary 1–10 cm in diameter, and may coalesce to form large areas of hardened skin. [2]

As the nodules age, they become bluish purple, brownish, yellowish, and finally green, similar to the color changes that occur in a resolving bruise. The nodules usually subside over a period of 2–6 weeks without ulceration or scarring.[3]

Less common variants of erythema nodosum include:

  • Ulcerating forms, seen in Crohn's disease [1]
  • Erythema contusiforme, a erythema nodosum lesion with subcutaneous haemorrhage [1]
  • Chronic erythema nodosum, more likely to be unilateral and migratory. [1]
  • Erythema nodosum migrans, (also known as subacute nodular migratory panniculitis of Vilanova and Piñol), a form of erythema nodosum with lesions that spread centrifugally with central clearing, [1] and a form of chronic erythema nodosum. [4]) is a form of septal panniculitis that is much less common than acute erythema nodosum.[5]:488
  • Lofgren's syndrome, a form of acute sarcoidosis with erythema nodosum, bilateral hilar adenopathy, fever, and often accompanied by joint symptoms.


In about 30-50% of cases, the cause of EN is unknown.[6]

Erythema nodosum is associated with a wide variety of conditions, including:

EN may also be due to excessive antibody production in lepromatous leprosy leading to deposition of immune complexes.[9]

There is an association with the HLA-B27 histocompatibility antigen, which is present in 65% of patients with erythema nodosum.[10]

A useful mnemonic for causes is SORE SHINS (Streptococci, OCP, Rickettsia, Eponymous (Bechet), Sulfonamides, Hansen's Disease (Leprosy), IBD, NHL, Sarcoidosis.[11]



Erythema nodosum is diagnosed clinically. A biopsy can be taken and examined microscopically to confirm an uncertain diagnosis. [3]:148 Microscopic examination usually reveals a neutrophilic infiltrate surrounding capillaries that results in septal thickening, with fibrotic changes in the fat around blood vessels. A characteristic microscopic finding is radial granulomas, well-defined nodular aggregates of histiocytes surrounding a stellate cleft. [2]

Additional evaluation should be performed to determine the underlying cause of erythema nodosum. This may include a full blood count, erythrocyte sedimentation rate (ESR), antistreptolysin-O (ASO) titer and throat culture, urinalysis, intradermal tuberculin test, and a chest x-ray.[12] The ESR is typically high, the C-reactive protein elevated, and the blood showing an increase in white blood cells. [3] :148

The ESR is initially very high, and falls as the nodules of erythema nodosum. The ASO titer is high in cases associated with a streptococcal throat infection. A chest X-ray should be performed to rule out pulmonary diseases, in particular sarcoidosis and Löfgren syndrome. [3] :148


Erythema nodosum is self limiting and usually resolves itself within 3–6 weeks. A recurring form does exist, and in children it is attributed to repeated infections with streptococcus.[9] Treatment should focus on the underlying cause. Symptoms can be treated with bedrest, leg elevation, compressive bandages, wet dressings, and nonsteroidal anti-inflammatory agents (NSAIDs). [2] NSAIDs are usually more effective at the onset of EN versus with chronic disease.

Potassium iodide can be used for persistent lesions whose cause remains unknown. Corticosteroids and colchicine can be used in severe refractory cases.[13][14] Thalidomide has been used successfully in the treatment of Erythema nodosum leprosum,[15] and it was approved by the U.S. FDA for this use in July 1998.[16]


Erythema nodosum is the most common form of panniculitis. It is most common in the ages of 20–30, and affects women 3–6 times more than men. [3] :148

About 15 percent of patients with inflammatory bowel disease develop erythema nodosum.[17]


This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.