Erythema nodosum is the name given to tender lumps on the legs and sometimes the arms. They are caused by inflammation of the fat or connective tissue beneath the skin.
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Erythema nodosum is thought to be a type of autoimmune reaction. It may be caused by:
Sometimes the cause of erythema nodosum is not known.
This condition is rare. It is more common in females and young adults aged 20-30 years old.
Having any of the causes listed above will only slightly increase your risk of the disorder.
You will be asked about your symptoms and medical history. A physical exam will be done, which may diagnose the problem based on a visual exam. You may be referred to a doctor that focuses on skin problems or infectious diseases.
Your bodily fluids and cells may be tested to look for a cause. This can be done with:
Images may be taken of your bodily structures. This can be done with a chest x-ray and other imaging tests.
If a cause can be identified, it will be treated. For the nodules themselves, pain relief is all that is needed. They tend to resolve on their own in about 6 weeks. They will not cause scarring. Treatment options include the following:
Pain relief includes:
Other medications such as steroids, may be necessary in severe cases.
Some of the infectious causes can be avoided by practicing good hygiene, which includes:
American Academy of Dermatology
Family Doctor—American Academy of Family Physicians
Canadian Dermatology Association
Erythema nodosum. EBSCO DynaMed Plus website. Available at:http://www.dynamed.com/topics/dmp~AN~T116219/Erythema-nodosumUpdated February 23, 2016. Accessed August 18, 2017.
Erythema nodosum. DermNet New Zealand website. Available at: https://www.dermnetnz.org/topics/erythema-nodosum. Accessed August 18, 2017.
Erythema nodosum. Better Health Channel website. Available at: https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/erythema-nodosum. Updated April 2016. Accessed August 18, 2017.
Requena L, Yus ES. Erythema nodosum. Dermatol Clin. 2008;26(4):425-438.
Last reviewed September 2018 by EBSCO Medical Review Board Michael Woods, MD, FAAP Last Updated: 8/7/2015