What is the treatment for erythema nodosum?

Treatment of Erythema Nodosum

Colchicine should be the first-line treatment for erythema nodosum, especially when it is the dominant lesion. 1

Understanding Erythema Nodosum

Erythema nodosum is the most common form of panniculitis, characterized by:

• Tender, erythematous, subcutaneous nodules (1-5 cm in diameter)
• Typically located on the anterior tibial areas (shins)
• Often accompanied by systemic symptoms including arthralgia and fatigue
• More common in women than men

Treatment Algorithm

First-Line Treatment

1. Identify and treat underlying causes if present:

   • Streptococcal infections (most common identifiable cause)
   • Tuberculosis
   • Sarcoidosis
   • Inflammatory bowel disease
   • Behçet's syndrome
   • Medications (oral contraceptives, antibiotics)

2. Symptomatic treatment:

   • Colchicine - first choice, especially effective when erythema nodosum is the dominant lesion 1, 2
   • Rest and elevation of affected limbs
   • NSAIDs (aspirin, naproxen, indomethacin) for pain management 3

Second-Line Treatment (for Severe Cases)

• Systemic corticosteroids for severe cases that don't respond to first-line therapy 2, 1
  • Use brief courses to minimize side effects
  • Ensure any underlying infection is ruled out before administration 3

Third-Line Treatment (for Resistant/Recurrent Cases)

• Immunomodulators:
  • Azathioprine 2, 1
  • TNF-α antagonists (infliximab, adalimumab) 2, 1

Special Considerations

Erythema Nodosum in Behçet's Syndrome

• Colchicine is particularly effective and should be the first choice 2, 1
• For resistant cases, consider azathioprine, thalidomide, interferon-alpha, or TNF-alpha inhibitors 2

Erythema Nodosum in Inflammatory Bowel Disease

• Treatment should focus on managing the underlying IBD activity 2, 1
• Systemic corticosteroids may be required in severe cases 2
• For resistant cases or frequent relapses, consider azathioprine, infliximab, or adalimumab 2

Monitoring and Prognosis

• Most cases resolve spontaneously within 3-6 weeks without scarring 3, 4
• Monitor for recurrence, which is more common in idiopathic cases (62%) than in secondary erythema nodosum 5
• Regular follow-up to assess treatment response and evaluate for signs of underlying disease progression

Diagnostic Evaluation

When evaluating a patient with suspected erythema nodosum, consider:

• Complete blood count with differential
• Erythrocyte sedimentation rate and/or C-reactive protein
• Testing for streptococcal infection (throat culture, rapid antigen test)
• Chest radiograph (to evaluate for tuberculosis or sarcoidosis)
• Additional testing based on clinical suspicion of specific underlying causes

Common Pitfalls to Avoid

1. Failing to identify and treat the underlying cause
2. Using systemic corticosteroids without ruling out infection
3. Mistaking other forms of panniculitis for erythema nodosum
4. Unnecessary biopsies for typical presentations (biopsy should be reserved for atypical cases)
5. Overlooking the possibility of recurrence, especially in idiopathic cases

Remember that erythema nodosum never ulcerates and heals without atrophy or scarring - if these features are present, consider alternative diagnoses.