erythema multiforme

Introduction

Self-limited mucocutaneous reaction.

Etiology

• systemic infection (~50%)
  • Herpes simplex (especially recurrent erythema multiforme minor)
  • Mycoplasma pneumoniae
  • Yersinia enterocolitica
• sensitivity to pharmacologic agent (~50%)
  • NSAIDs
    • phenylbutazone
    • salicylates
  • anticonvulsants
    • barbiturates
    • phenytoin
  • sulfonamides
  • antibotics
    • penicillins
    • tetracyclines
  • thiazides
  • chlorpropamide
  • codeine
  • sulfones
  • allopurinol
• pregnancy
• food allergy
• X-rays
• cancer
• connective tissue disease
• inflammatory bowel disease

Epidemiology

• adolescents & young adults
• more frequent in males than females

Pathology

• dermal blood vessel involvement
• extravasation of erythrocytes with resultant purpura
• perivascular mononuclear infiltrate
• edema of the upper dermis
• eosinophilic necrosis of keratinocytes with subepidermal bulla formation
• toxic epidermal necrolysis (TEN) in severe cases

Clinical manifestations

• mucous membrane manifestations (70%)
  • mucosal erosion
  • painful
  • lips, oropharynx, nasal, conjunctival, vulvar, anal
  • sudden appearance
  • pharyngitis
  • vulvitis & balanitis may interfere with micturition
  • cheilitis & stomatitis may interfere with eating
• skin manifestations
  • erythematous plaques on skin &/or mucous membranes
  • sudden appearance
  • sharply demarcated
  • symmetric distribution
  • "target lesions" (3 zones) resulting from papule or vesicle formation in the center of a plaque
  • resolution without scarring
  • lesions may last up to 2 weeks
  • predilection for dorsum of hands, palms & soles, feet, face, elbows, knees, penis (50%) & vulva
  • pruritus
  • positive Nikolsky sign in more severe forms
• other manifestations
  • systemic symptoms in more severe forms
    • mild fever
    • arthralgias
    • myalgias
    • malaise
  • eye manifestations
    • anterior uveitis
    • corneal ulcers
    • conjunctivitis
• often recurrent
• severe life-threatening variant
  • necrotizing tracheobronchitis
  • meningitis
  • renal tubular necrosis
  • Stevens-Johnson syndrome -> toxic epidermal necrolysis

* images

Complications

• secondary bacterial infection which may result in scarring especially on mucous membranes of eyes & urethra
• not fatal

Differential diagnosis

• acute erythematous plaques
  • drug eruption
  • psoriasis
  • secondary syphilis
  • urticaria
• acute oral erosions
  • Herpes
  • pemphigus
  • lupus erythematosus
• annular lesions
  • erythema migrans of Lyme disease
  • herald patch of Pityriasis rosea
  • Tinea corporis

Management

• supportive care
• acyclovir for control of Herpes simplex
  • does not shorten duration of symptoms
  • chronic suppressive therapy may diminish recurrence
• treatment & prevention of bacterial infection
  • azithromycin for pneumonia due to Mycoplasma pneumoniae ' - penicillin for secondary syphilis
• prednisone 50-80 mg PO QD in divided doses, rapidly tapered
  • no controlled studies
  • reserve for severely ill patients
  • not effective; do not use

More general terms

• vesiculobullous dermatitis

Additional terms

• acyclovir (ACV, Zovirax, Sitavig)
• erythema nodosum (septal panniculitis)
• Herpes simplex (HSV) or Herpes hominis
• Nikolsky's sign
• pemphigus
• prednisone (Deltasone, Orasone, Liquid Pred, Meticortin, Rayos)
• psoriasis
• Stevens-Johnson syndrome (SJS)
• syphilis
• systemic lupus erythematosus
• toxic (bullous) epidermal necrolysis (Lyell syndrome, TEN)
• urticaria (hives)