Erythema Nodosum
all information

Erythema Nodosum

Pronounced: AIR-uh-THEE-ma no-DOSE-um

En Español (Spanish Version)


Erythema nodosum is the name given to extremely tender lumps on the legs and sometimes the arms caused by inflammation of the fat beneath the skin (panniculitis). The bumps look like bruises and change color in the same way, from pink to blue to brown. They are often accompanied by fever, joint pain, and redness around the eyes. They may continue to erupt for a week to 10 days, but they eventually resolve, normally within 1-2 months.

Erythema Nodosum

Erythema  Nodusum

© 2008 Nucleus Medical Art, Inc.


Erythema nodosum is presumed to be a type of allergic reaction either to infection or to a prescription drug. It may also be associated with inflammatory conditions. A cause is often not identified.

Risk Factors

Since erythema nodosum is relatively rare, developing any of these diseases or taking these medications will only slightly increase your risk of the disorder. Erythema nodosum is more common in young adults (20-30 years old) and females.


If you experience something resembling this condition, do not assume it is erythema nodosum. Sores that seem to be erythema nodosum should be evaluated by your physician.

  • Very tender deep-seated lumps, like bruises, usually located on your shins
  • Associated joint pain and fever


Your doctor will ask about your symptoms, medications, and medical history, and perform a physical exam. You may be referred to a specialist in skin problems (dermatology) or infectious diseases.

Tests may include the following:

  • Blood and urine samples
  • Cultures of various bodily fluids
  • Chest x-ray and other imaging tests
  • PPD (skin test for tuberculosis)
  • Biopsy of a lesion


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 six weeks without scarring. Treatment options include the following:

Pain Relief

  • Bedrest and elevation of legs
  • Wet compresses
  • Aspirin or similar nonsteroidal anti-inflammatory
  • Potassium iodide
    • Potassium iodide 300-600 milligrams per day for up to two months may alleviate the discomfort (but iodides can also cause the problem)

Steroid Treatment

This may be necessary in severe cases.


Some of the causes of erythema nodosum can be avoided, but the condition is rare enough that nothing but the most obvious measures are worthwhile.


American Academy of Dermatology

American Osteopathic College of Dermatology

Dermnet NZ

University of Maryland Medical Center


Canadian Dermatology Association


Beers MH, Berkow R. The Merck Manual . 17th ed. Merck & Co. West Point PA; 1999.

DermAtlas. Johns Hopkins University. Available at: . Accessed September 15, 2005.

Erythema nodosum. The Australasian College of Dermatologists Available at: . Accessed September 15, 2005.

Last reviewed January 2008 by Ross Zeltser, MD

Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.

Your Health and Happiness