Does erythema nodosum (EN) itch?

Erythema Nodosum and Pruritus

Erythema nodosum is typically characterized by tender, painful nodules rather than itchy lesions, with pruritus not being a common or defining symptom of this condition. 1

Clinical Characteristics of Erythema Nodosum

Typical Presentation

• Erythema nodosum presents as raised, tender, erythematous subcutaneous nodules (1-5 cm in diameter)
• Most commonly located on the anterior tibial areas (shins)
• Lesions are typically bilateral and symmetrical 2, 3
• Initially bright red, then evolve to livid red/purplish, and finally exhibit yellow or greenish appearance resembling bruises 3

Key Symptoms

• Pain and tenderness are the predominant symptoms
• Nodules are warm to touch
• Often accompanied by systemic symptoms including:
  • Fever
  • Arthralgia
  • Fatigue 1

What Erythema Nodosum is NOT Associated With

• Pruritus (itching) is not a characteristic feature
• Ulceration never occurs
• Lesions heal without atrophy or scarring 3

Diagnostic Considerations

Physical Examination

• Firm, tender, erythematous subcutaneous nodules
• Typically 1-5 cm in diameter
• Diagnosis is primarily made on clinical grounds 2
• In atypical cases, skin biopsy may be helpful 2

Histopathological Features

• Septal panniculitis without vasculitis
• Thickened septa of subcutaneous fat infiltrated by inflammatory cells
• Presence of Miescher's radial granulomas (small nodular aggregations of histiocytes arranged radially around a central cleft) 3

Differential Diagnosis

When evaluating nodular skin lesions with pruritus, consider these alternative diagnoses:

• Insect bites (typically pruritic)
• Contact dermatitis (often pruritic)
• Urticaria (intensely pruritic)
• Erythema multiforme (may have some pruritus)
• Other forms of panniculitis (may have variable symptoms)

Management Approach

Underlying Cause Identification

• Identify and treat underlying causes 1:
  • Streptococcal infections
  • Tuberculosis
  • Sarcoidosis
  • Inflammatory bowel disease
  • Behçet's syndrome
  • Medication reactions

Treatment Options

1. First-line treatment: Colchicine 1
2. For severe cases: Systemic corticosteroids 1
3. For resistant cases: Immunomodulators (azathioprine, TNF-α antagonists) 1
4. Supportive care:
   • Rest and elevation of affected limbs
   • Compression stockings
   • Pain management with NSAIDs 1, 3

Clinical Pearls

• Erythema nodosum is more common in women than men 1
• Typically self-limited, resolving within 3-6 weeks without scarring 1
• May be the first sign of systemic disease such as tuberculosis, sarcoidosis, or inflammatory bowel disease 4
• Pain, not itching, should guide your diagnostic thinking when considering erythema nodosum

Monitoring and Follow-up

• Regular follow-up to assess treatment response
• Monitor for recurrence after treatment discontinuation
• Evaluate for signs of underlying disease progression 1

In summary, when evaluating a patient with suspected erythema nodosum who reports itching, consider alternative diagnoses, as pruritus is not a typical feature of this condition. The hallmark symptoms are tenderness and pain in the nodular lesions.