How Erythema Nodosum Is Connected to IBD

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Skin disorders are a common extraintestinal symptom of inflammatory bowel disease (IBD), occurring in up to 25% of people with ulcerative colitis and Crohn's disease. Some of these skin conditions are called pyoderma gangrenosum, aphthous ulcers, and erythema nodosum.

Erythema nodosum is a skin condition that most often affects people with Crohn's disease, but can also develop in those who have ulcerative colitis. It is estimated to occur in between 10% to 15% of people with IBD, making it a fairly common complication. This condition often goes away on its own or improves when the underlying IBD is under control. People with IBD need to know the signs of this skin condition to diagnose it early.

doctor examining arm of patient
Thomas_EyeDesign / Getty Images


Erythema nodosum are painful red nodules (or lesions) that most often develop on the arms or lower legs but may also appear in other places on the body. This condition is more prevalent in adults than children, and more common in women than in men.

The formation of erythema nodosum lesions may be preceded by a flu-like feeling or generalized pain in the joints. The lesions themselves may first appear as tender, red nodules, becoming hard and painful in the first week. The lesions may appear bluish or black and blue and feel as if they contain fluid during the second week and then slowly turn yellowish before healing. The lesions last for about two weeks but may be replaced by new lesions when they resolve. The cycle may be over after the first batch of lesions appear and then heal, or it may continue for several weeks to months with new lesions appearing.

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Erythema nodosum on legs
Erythema nodosum on legs. DermNet / CC BY-NC-ND


In IBD, erythema nodosum may appear for the first time during a flare-up. It may follow the course of IBD, which means that it improves when the flare-up is better controlled.

Other causes of erythema nodosum include bacterial infections, fungal infections, Hodgkin's lymphoma (Hodgkin's disease), sarcoidosis, Behçet's disease (a rare disorder causing inflammation in blood vessels), pregnancy, and reactions to medications (such as sulfa drugs).


When erythema nodosum occurs in a person with diagnosed IBD, there may be no tests done, as the condition is known to occur with IBD and the lesions are recognizable. In people who do not have IBD, a physician may decide it's necessary to order tests, such as X-rays, blood cultures, and biopsy, to rule out an infection or another disease or condition.


Because erythema nodosum tends to resolve on its own, there is usually no specific treatment to help the lesions heal. Treatment is usually only needed to help control the pain caused by the lesions or in the joints. This may include cool compresses, leg elevation, and rest.

Nonsteroidal anti-inflammatory drugs (NSAIDs) may also be helpful in providing pain relief, but they should be used with caution in people who have IBD. NSAIDs may cause a flare-up in some people with IBD, and therefore these drugs should only be used under the direct supervision of a gastroenterologist. Dermatologists or other physicians who treat skin disorders may not realize that NSAIDs have this negative effect on IBD. For this reason, people with IBD should question new prescriptions and discuss them with a gastroenterologist before taking them.

Corticosteroids, potassium iodide, and antithyroid agents may also be used in severe or chronic cases of erythema nodosum. Limiting activity may also be recommended to help decrease the time it takes for the lesions and other symptoms to resolve.

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By Amber J. Tresca
Amber J. Tresca is a freelance writer and speaker who covers digestive conditions, including IBD. She was diagnosed with ulcerative colitis at age 16.