Erythema Nodosum

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Medical Author: William C. Shiel Jr., MD, FACP, FACR
Medical Editor: Dennis Lee, MD

• What is erythema nodosum?
• What causes erythema nodosum?
• How is erythema nodosum diagnosed?
• How is erythema nodosum treated?
• Patient Discussions: Erythema Nodosum - Describe Your Experience
• Find a local Dermatologist in your town

Featured patient discussions on erythema nodosum "I have had outbreaks of erythema nodosum since 1993. My dermatologist told me it was an allergic reaction to something in my blood stream. She suggested I pay attention to what I have been eating when I start to break out in these painful bumps. So I did. It was soy...anything with soy in it is a big "no" for me! That was what triggered it. To this day, if I slip up and eat something with soy in it, I will break out on my legs. So I suggest to everybody out there who is stumped and cannot figure out why you're breaking out with these painful bumps, pay attention to what you're eating! It may be something as simple as what you're putting in your mouth! I hope this helps, because I know how painful this can be!" Read all erythema nodosum comments » Top Searched Erythema Nodosum Terms: causes, cancer, diagnosing, treatment, pregnancy, sarcoidosis, malaise, Streptococcal infections, colitis Patient Discussions are not a substitute for professional medical advice, or treatment. See the disclaimer at the bottom of the comments page.

What is erythema nodosum?

Erythema nodosum is a type of skin inflammation that is located in a certain portion of the fatty layer of skin. Erythema nodosum (also called EN) results in reddish, painful, tender lumps most commonly located in the front of the legs below the knees. The tender lumps, or nodules, of erythema nodosum range in size from 1 to 5 centimeters. The nodular swelling is caused by a special pattern of inflammation in the fatty layer of skin.

Erythema nodosum can be self-limited and resolve on its own in three to six weeks. Upon resolution, it may leave only a temporary bruised appearance or leave a chronic indentation in the skin where the fatty layer has been injured.

There are several scenarios for the outcome of erythema nodosum. Typically, these areas of nodular tenderness range in size from about a dime to a quarter and they may be tender and inflamed off and on for a period of weeks. They usually then resolve spontaneously, each one of the little areas of inflammation shrinking down and then becoming flat rather than raised and inflamed. They leave a bruised appearance. Then, they resolve spontaneously completely. Other lesions can sometimes pop up elsewhere. This may occur for periods of weeks to months and then eventually goes away. However, chronic erythema nodosum that may last for years is another pattern. Chronic erythema nodosum, with intermittent recurrences, can occur with or without an underlying disease present.

What causes erythema nodosum?

Erythema nodosum may occur as an isolated condition or in association with other conditions. Conditions that are associated with erythema nodosum include medications (sulfa-related drugs, birth control pills, estrogens), strep throat, Cat scratch disease, fungal diseases, infectious mononucleosis, sarcoidosis, Behcet's disease, inflammatory bowel diseases (Crohn's disease and ulcerative colitis), and normal pregnancy.

Erythema Nodosum - Describe Your Experience

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Please describe your experience with erythema nodosum.

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