What Is Erythema Nodosum?
Erythema nodosum is an inflammatory skin condition that causes painful lumps to form under the skin. These bumps most often appear on the front of the lower legs, but they can also develop on the thighs, arms, or other areas of the body.
The condition is usually linked to the body reacting to an infection, medication, or another health problem. In some people, no clear cause is found. While the bumps can be uncomfortable, erythema nodosum often improves over time with supportive care and treatment of the underlying cause.
Several conditions and triggers may lead to erythema nodosum, including:
- Strep throat or other infections
- Inflammatory bowel diseases such as Crohn’s disease or ulcerative colitis
- Sarcoidosis
- Certain fungal or lung infections
- Pregnancy
- Reactions to medications, including some antibiotics or birth control pills
Symptoms
Erythema nodosum can develop suddenly and may be accompanied by other symptoms throughout the body.
Common symptoms include:
- Tender red or purple bumps on the shins
- Pain or warmth in the affected areas
- Fatigue
- Fever
- Joint pain or swelling
- A general feeling of being unwell
As the bumps heal, they may fade and look similar to bruises.
How Is It Diagnosed?
Your healthcare provider will begin with a physical exam and discussion about your symptoms, medications, and medical history. Because erythema nodosum can be connected to other health conditions, additional testing may help identify the cause.
Testing may include:
- Blood tests
- Throat swab for strep infection
- Chest X-ray or other imaging
- Skin biopsy
- Other tests based on your symptoms and health history
Finding and treating the underlying cause is an important part of care.
How Is It Treated?
Treatment focuses on easing symptoms and addressing any underlying condition causing the inflammation. Mild cases may improve on their own within a few weeks.
Common treatments may include:
- Rest and elevating the legs
- Anti-inflammatory medications to reduce pain and swelling
- Antibiotics if a bacterial infection is present
- Stopping a medication that may be triggering symptoms
- Corticosteroids for more severe inflammation
Most people recover fully, although the condition can return in some cases.
