Erythema nodosum most commonly occurs on the shins, followed by the thighs and forearms.
Erythema nodosum (EN) is a condition where painful, red lesions appear on the skin, typically due to the inflammation of fat underneath the skin. People who have EN may also suffer from fevers, body aches, tiredness, and pain in the eyes and joints.
EN is caused by the immune system overreacting to infections, medications, or other internal conditions.
- Infections: strep throat infection, tuberculosis, and leprosy (in rare cases)
- Medications: salicylates, nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen and naproxen, birth control pills, and sulfa-containing drugs
- Internal conditions: inflammatory bowel diseases (ulcerative colitis, Crohn’s disease), sarcoidosis, pregnancy, or cancers
If a medication is identified as a cause, it should be stopped. Otherwise, cool compresses and compression stockings can help reduce pain and swelling for temporary relief.
Medications used to treat erythema nodosum include:
- Infections may be treated with antibiotics or antifungals
- Topical or oral steroids can reduce inflammation and swelling
- Potassium iodide can reduce local swelling and fevers