Erythema Nodosum: Symptoms And Causes

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Erythema nodosum is a skin condition which causes painful swollen red or purple bumps and most commonly they are located on the shins. In some cases, the bumps can also form on other parts of the body. This condition is most common form of panniculitis, which is an inflammation of the layer underneath your skin. It is often caused by an immune response to an infection or a reaction to drugs that you have taken. [1]

It is noticed that about 5% of pregnant women develop erythema nodosum. This may be due to the increased estrogen levels during the pregnancy. The erythema nodosum is treated in much the same way during the pregnancy as it is in the women who are not pregnant. [2] But, some of the medicines, like NSAIDs, which are used to treat erythema nodosum, cannot be given to pregnant women. Compression stocking and bed rest can help to manage pain and other symptoms. [3]

Your obstetrician will tell you which the best way to control the erythema nodosum during the pregnancy is. The erythema nodosum should fade away within a few weeks. Usually, this is harmless condition, but it can be a sign of underlying condition, an abnormal response to an allergen or medication or other inflammatory conditions.

erythema nodosum causes

Erythema nodosum symptoms

The main symptom of erythema nodosum is red and painful bump on the lower part of your legs. In some cases, these bumps can also appear on your face, torso, arms and thighs. These lumps can be one – half inch up to 4 inches. You can have anywhere from 2 – 50 of them. It’s bumps are painful and they may feel hot. They start out as red and then, they turn into purple, looking like bruises as they heal. Also, they flatten out while healing. These bumps can last for up to two weeks and new bumps can keep forming up to 6 weeks. Also, there can be other symptoms of it [4], such as

  • Diarrhea
  • Stomach pain
  • Weight loss
  • Sore throat
  • Cough
  • Enlarged lymph nodes in the chest
  • Ankle swelling
  • Pain in the legs
  • Joint pain
  • Fatigue
  • Fever

Most erythema nodosum sores are usually:

  • Shiny in appearance
  • Varying in number, from two to more than fifty
  • Varying in size from a grape to a grapefruit, but mostly between 1 cm and 5 cm
  • A non – ulcerating or not causing breaks or tears in the surface of the skin
  • Rounded in shape
  • Slightly raised
  • Forming on the front of the shins, but also sometimes the ankles, knees, thighs and forearms
  • On both sides of the body equally
  • In color – bright red for a week to 10 days then fade to purple or blue
  • Hot to touch
  • Very painful

In rare cases, these spots may bond together or form a crescent – shaped ring which spreads for a few days before fading. With the proper rest, this will resolve on its own within 1 – 2 months, with new sores continuing to develop or spread throughout the first few weeks. In some cases, it can last for six months or more and this is more likely because it is caused by an underlying medical condition or untreated infection.

Erythema nodosum causes

In more than half of all cases of erythema nodosum, the cause for it is not known. The erythema nodosum often starts after you have had an infection or you have used certain medicines. Also, doctors believe that the erythema nodosum can be caused by an immune system overreaction to bacteria and other substances which you are exposed to. [1] The most common causes for erythema nodosum include:

  • In rare cases, cancer [5]
  • Pregnancy [2]
  • Inflammatory bowel disease, ulcerative colitis or Crohn’s disease
  • Coccidioidomycosis, which is an infection of the lungs and the upper respiratory tract [6]
  • Sarcoidosis, which is a condition that can cause inflammation in many parts of your body [7]
  • Reactions to drugs, such as birth control pills, bromides, iodides, salicylates and antibiotics (sulfonamides and forms of penicillin)

Most often, the erythema nodosum affects people between ages 20 – 40. It is noticed than women have 6 times more chances of developing erythema nodosum compared to men. But, the erythema nodosum can happen in people of any age and in both sexes. [8]


[1] Chowaniec M, Starba A, Wiland P. Erythema nodosum – review of the literature. Reumatologia. 2016;54(2):79–82. doi:10.5114/reum.2016.60217

[2] Acosta A, Haver MC, Kelly B. Etiology and therapeutic management of erythema nodosum during pregnancy: An update. American Journal of Clinical Dermatology. 2013;14(3). doi:10.1007/s40257-013-0024-x

[3] Golisch KB, Gottesman SP, Segal RJ. Compression stockings as an effective treatment for erythema nodosum: Case series. International Journal of Women’s Dermatology. 2017;3(4):231–3. doi:10.1016/j.ijwd.2017.09.001

[4] Rizvi Z, Iqbal T, Javed A, Rizvi A. Erythema nodosum: A consequence of tuberculosis. Cureus. 2019;11(5):e4724. doi:10.7759/cureus.4724

[5] Xu X, Liang G, Duan M, Zhang L. Acute myeloid leukemia presenting as erythema nodosum: A case report. Medicine. 2017;96(47):e8666.

[6] Chen CM, Lee HE, Li SY. Coccidioidomycosis with cutaneous manifestation of erythema nodosum in Taiwan. Dermatologica Sinica. 2010;28(4):154-8.

[7] Ungprasert P, Ryu JH, Matteson EL. Clinical manifestations, diagnosis, and treatment of sarcoidosis. Mayo Clinic Proceedings: Innovations, Quality & Outcomes. 2019;3(3):358–75. doi:10.1016/j.mayocpiqo.2019.04.006

[8] Suter P, Mooser B, Huu Thien HPP. Erythema nodosum as a cutaneous manifestation of COVID-19 infection. MJ Case Reports CP. 2020;13:e236613.


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