Definition

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.

Erythema Nodosum

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Causes

Erythema nodosum may be caused by:

• Infections from a:
  • Virus
  • Bacteria, especially strep throat
  • Fungus
• Inflammatory conditions, such as:
  • Ulcerative colitis
  • Crohn’s disease
  • Sarcoidosis
• Pregnancy
• Medicines, such as:
  • Birth control pills
  • Sulfa drugs and some other antibiotics
  • Iodides
  • Bromides
  • Leukotriene modifiers
  • Proton pump inhibitors
• Certain types of cancer, such as:
  • Lymphoma
  • Leukemia

Sometimes the cause is not known.

Risk Factors

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

Symptoms come on suddenly. They may be:

• Very tender, deep lumps, like bruises, that:
  • 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

Diagnosis

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

Treatment

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.

Prevention

There are no known guidelines for preventing this condition.