What is the treatment for erythema nodosum?

Treatment of Erythema Nodosum

Treatment of erythema nodosum should prioritize identifying and treating any underlying cause, with NSAIDs as first-line symptomatic therapy, reserving systemic corticosteroids for severe cases only after excluding infectious etiologies. 1, 2

Initial Management Approach

The cornerstone of treatment is addressing the underlying trigger while providing symptomatic relief 2:

• NSAIDs are the primary treatment for pain and inflammation in all cases of erythema nodosum 2, 3
• Identify and treat the underlying cause when present (streptococcal pharyngitis, tuberculosis, sarcoidosis, inflammatory bowel disease, fungal infections, or medication-related) 2, 4
• Supportive care including rest, leg elevation, and compression when appropriate 4

Disease-Specific Treatment Strategies

IBD-Associated Erythema Nodosum

When erythema nodosum occurs with inflammatory bowel disease 1:

• Treatment is based on managing the underlying IBD since EN typically correlates with disease activity 1
• Systemic corticosteroids are required in severe cases with significant inflammation 1, 2
• For relapsing or resistant cases, escalate to immunomodulators (azathioprine) or anti-TNF biologics (infliximab or adalimumab) 1, 2

Behçet's Disease-Associated Erythema Nodosum

• Colchicine should be preferred when erythema nodosum is the dominant lesion in Behçet's disease 1, 2
• Topical corticosteroids for isolated lesions 1
• Azathioprine, interferon-alpha, or TNF-alpha antagonists for resistant cases 1

Infection-Related Erythema Nodosum

• For streptococcal pharyngitis: Treat with appropriate antibiotics 4, 5
• For coccidioidomycosis or histoplasmosis: NSAIDs alone are sufficient; antifungal therapy is not recommended for the EN itself 2
• For tuberculosis: Appropriate antimicrobial treatment is essential 3

Escalation Strategy for Refractory Cases

When standard therapy fails 1, 2:

1. Potassium iodide as an alternative oral agent 3
2. Colchicine particularly effective for recurrent cases 3
3. Azathioprine for frequent relapses, especially in IBD-associated EN 1, 2
4. TNF-alpha inhibitors (infliximab or adalimumab) for the most resistant cases 1, 2
5. Hydroxychloroquine may be considered when EN is associated with sarcoidosis 2

Critical Safety Considerations

Before initiating systemic corticosteroids, infectious causes must be excluded 2:

• Rule out tuberculosis with PPD testing and chest imaging in appropriate risk populations 4, 5
• Exclude active streptococcal infection with throat culture, rapid antigen test, or ASO titers 4, 5
• Consider fungal infections in endemic areas 2, 4

Common pitfall: Starting corticosteroids without adequate infectious disease workup can worsen underlying tuberculosis or fungal infections 2

Monitoring and Follow-up

• Monitor for disease activity in associated systemic conditions like IBD or sarcoidosis 2
• Recurrent EN warrants reassessment for persistent underlying disease activity 2
• Most cases are self-limited and resolve within 3-6 weeks without treatment 6

When Biopsy is Indicated

• Clinical diagnosis is usually sufficient for typical presentations 1
• Biopsy is reserved for atypical cases to confirm diagnosis and exclude other conditions 1, 2
• Histology shows septal panniculitis without vasculitis when performed 4