What is the best management approach for erythema multiforme?

Management of Erythema Multiforme

The best management approach for erythema multiforme includes identifying and treating the underlying cause, providing symptomatic relief with topical corticosteroids as first-line therapy, and considering systemic corticosteroids for severe cases. 1

Diagnosis and Classification

• Distinguish EM from Stevens-Johnson Syndrome (SJS) based on clinical presentation:
  • EM: Acral distribution with target lesions and limited mucosal involvement
  • SJS: Widespread erythematous/purpuric macules with blisters and extensive mucosal involvement 1
• Biopsy may help in unclear cases, with subepidermal cleavage characteristic of SJS/TEN 2

Initial Assessment

1. Identify and address underlying triggers:

   • Herpes simplex virus (most common cause)
   • Mycoplasma pneumoniae infection
   • Medications (antibiotics, anticonvulsants, NSAIDs)
   • Other viral infections (EBV, HCV, Coxsackie)

2. Document clinical features:

   • Distribution and morphology of lesions
   • Mucosal involvement (oral, ocular, genital)
   • Extent of involvement (% body surface area)

Treatment Algorithm

1. Mild Cutaneous EM (EM Minor)

• First-line therapy: High-potency topical corticosteroids applied to affected areas 2-3 times daily 1
• Symptomatic relief: Oral antihistamines for pruritus
• Discontinue any potential culprit medications 2

2. EM with Mucosal Involvement (EM Major)

• Topical therapy:
  • High-potency corticosteroids for skin lesions
  • Antiseptic or anesthetic solutions for mucosal involvement 1, 3
• Systemic therapy:
  • Prednisone 40-60 mg daily for 5-7 days with taper 1, 4
  • Maintain adequate hydration and electrolyte balance 5

3. HSV-Associated EM

• Acute treatment: Acyclovir 400 mg three times daily for 7-10 days 1
• Prophylaxis for recurrent HSV-EM:
  • Acyclovir 400 mg twice daily or
  • Valacyclovir 500 mg daily 1, 6
• Note: Topical prophylactic treatment with acyclovir is not effective in preventing recurrent episodes 6

4. Severe or Recurrent EM

• Second-line therapies for patients not responding to first-line treatment:
  • Immunosuppressive agents
  • Dapsone (for cases resistant to antivirals) 6
  • Consider newer options like JAK inhibitors or apremilast for refractory cases 6

Special Considerations

• Ocular involvement: Urgent ophthalmology consultation to prevent scarring and long-term sequelae
• Extensive mucosal involvement: May require hospitalization for IV fluids and electrolyte repletion 5
• Recurrent EM: Identify triggers and provide prophylactic therapy; consider long-term antiviral prophylaxis for HSV-associated recurrent EM

Monitoring and Follow-up

• Monitor for progression to more severe forms (SJS/TEN)
• Follow up within 1-2 weeks to assess response to treatment
• Most cases resolve within 2-3 weeks without scarring 1
• Long-term sequelae are more common with mucosal involvement, particularly ocular complications

Pitfalls to Avoid

• Misdiagnosing EM as urticaria (EM lesions are fixed for at least 7 days, while urticarial lesions typically resolve within 24 hours) 5
• Confusing EM with SJS/TEN, which requires more aggressive management 2, 1
• Failing to identify and address the underlying cause, particularly HSV infection or medication triggers
• Inadequate treatment of mucosal involvement, which can lead to scarring and long-term complications