Erythema nodosum is a rare condition where tender lumps form on the skin. It is due to inflammation of fat or connective tissue beneath the skin.
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Erythema nodosum may be caused by:
- Bacteria, especially strep throat
- Inflammatory conditions, such as:
Medicines, such as:
- Birth control pills
- Sulfa drugs and some other antibiotics
- Leukotriene modifiers
- Proton pump inhibitors
Certain types of cancer, such as:
Sometimes the cause is not known.
This condition is more common in females and young adults aged 20 to 30 years old.
The risk of this problem is low. It is only slightly higher in those who have the causes listed above.
Symptoms come on suddenly. They may be:
Very tender, deep lumps, like bruises,
- Change color, from pink to blue to brown
- Are usually found on the shins
- May also appear on the arms, trunk, neck, and head
- Accompanied by flu-like symptoms and joint pain—these can also appear 1 to 3 weeks before the lumps
The doctor will ask about your symptoms and health history. A physical exam will be done. This may be enough to diagnose the problem.
Tests may be done to look for a cause. They may be:
- Blood and urine tests
- Cultures or a throat swab for strep
- PPD skin test for tuberculosis
- Biopsy of one of the skin lumps
- Chest x-rays
The goal is to manage symptoms and treat any underlying causes. The lumps tend to go away on their own. This may take up to 6 weeks.
Pain will be eased with:
- Bed rest and elevation of legs
- Wet compresses
- Aspirin, except in children
- Nonsteroidal anti-inflammatory drugs (NSAIDs)
- Potassium iodide
If symptoms are severe, other medicines may be given, such as steroids.
There are no known guidelines for preventing this condition.
American Academy of Dermatology
Family Doctor—American Academy of Family Physicians
Canadian Dermatology Association
Erythema nodosum. EBSCO DynaMed website. Available at:https://www.dynamed.com/condition/erythema-nodosum Accessed February 19, 2021.
Erythema nodosum. DermNet New Zealand website. Available at: https://www.dermnetnz.org/topics/erythema-nodosum. Accessed February 19, 2021.
Erythema nodosum. Better Health Channel website. Available at: https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/erythema-nodosum. Accessed February 19, 2021.
Leung AKC, Leong KF, et al. Erythema nodosum. World J Pediatr. 2018;14(6):548-554.
Last reviewed January 2021 by EBSCO Medical Review Board Mary Beth Seymour, RN Last Updated: 2/19/2021