What is the best management approach for erythema multiforme?

Management of Erythema Multiforme

The best management approach for erythema multiforme (EM) is to identify and treat the underlying trigger, with first-line therapy consisting of topical corticosteroids for cutaneous lesions and antiviral therapy for HSV-associated cases. 1

Diagnosis and Classification

• EM is characterized by target-like lesions with acral distribution and limited mucosal involvement
• Must be distinguished from Stevens-Johnson Syndrome (SJS), which presents with widespread erythematous/purpuric macules, blisters, and extensive mucosal involvement 1
• Biopsy may help in unclear cases, with subepidermal cleavage characteristic of SJS 1

Identifying Underlying Triggers

Identifying and addressing the underlying cause is crucial for effective management:

• Herpes simplex virus (HSV): Most common cause of EM 1, 2
• Other infections: Mycoplasma pneumoniae, EBV, HCV, Coxsackie virus 1, 3
• Medications: Antibiotics, anticonvulsants, NSAIDs 1

Treatment Algorithm

1. Acute Management

• Discontinue potential culprit medications if drug-induced 1
• For cutaneous lesions: Apply high-potency topical corticosteroids to affected areas 2-3 times daily 1, 2
• For severe cases: Consider systemic corticosteroids (prednisone 40-60 mg daily for 5-7 days with taper) 1, 4
  • Prednisone is FDA-approved for severe erythema multiforme 4
• For HSV-associated EM: Administer acyclovir 400 mg three times daily for 7-10 days 1
• For severe mucosal involvement: Consider hospitalization for IV fluids and electrolyte repletion 5

2. Management of Recurrent EM

• For HSV-associated recurrent EM: Implement antiviral prophylaxis with:
  • Acyclovir 400 mg twice daily OR
  • Valacyclovir 500 mg daily 1, 6
• For cases resistant to antivirals:
  • Consider dapsone as a second-line agent 6
  • For highly resistant cases, azathioprine has shown complete disease suppression 6
  • Other potential options include JAK-inhibitors or apremilast for refractory cases 3

Special Considerations

• Mucosal involvement: Use antiseptic or anesthetic solutions for symptomatic relief 2
• Pediatric cases: Generally have lower mortality compared to adults 1
• Long-term monitoring: Particularly important for patients with ocular involvement due to potential complications 1

Common Pitfalls to Avoid

1. Misdiagnosis: Don't confuse EM with SJS or urticaria (EM lesions persist for at least 7 days, while urticarial lesions typically resolve within 1 day) 5

2. Inadequate trigger identification: Thorough investigation of potential infectious causes and medication review is essential

3. Ineffective prophylaxis: Topical acyclovir is generally ineffective for preventing recurrent HSV-associated EM; oral antiviral therapy is preferred 3

4. Delayed treatment: Early intervention, especially for mucosal involvement, can prevent complications

Most cases of EM are self-limited and resolve within 2-3 weeks, but proper management can reduce symptoms and prevent recurrence 1, 2.