II. Epidemiology

  1. Age of onset 60 to 80 years old
  2. Men and women affected equally
  3. Incidence: 7 per 1 million in U.S.

III. Pathophysiology

  1. Autoimmune Subepidermal Blistering
  2. Mediated by IgG auto-antibodies that target basement membrane hemidesmosome at dermal-epidermal junction

IV. Causes

  1. Idiopathic (85% of cases)
  2. Specific trigger (15% of cases)
    1. Radiation Therapy
    2. Burn Injury
    3. Immunization
    4. Surgery
    5. Trauma
    6. Medications (esp. Furosemide)

V. Symptoms

  1. Pruritus
  2. Lesions may be tender at borders

VI. Signs

  1. First phase (weeks to months)
    1. Initial Urticarial, Eczematous or erythematous papular lesions
    2. Lesions start on extremities and spread centrally
    3. Flexor creases (e.g. axilla, inguinal) are often affected
    4. Intense Pruritus
  2. Second phase
    1. Develops into large tense bullae (1 to 4 cm in diameter) after weeks to months
      1. Contain clear fluid or may at times be hemorrhagic
      2. Form over an erythematous base
    2. Diffuse cutaneous involvement
      1. Often involves lower legs, Forearms, thighs, groin
      2. Also involves Abdomen
      3. Mucosal involvement in 10 to 30% of patients
        1. Mucusa much less affected than in pemphigous vulgaris
    3. No scar formation
    4. Milia may form at previously involved sites
    5. Nikolsky Sign is absent (contrast with Pemphigus lesions)
      1. Thick walled bullae

VII. Labs

  1. Histology
    1. Subepidermal Blister
    2. Superficial dermal inflammation (Eosinophils)
  2. Immunofluorescence
    1. IgG and C3 deposition along basement membrane zone

VIII. Differential Diagnosis

IX. Management

  1. Goals
    1. Limit lesion spread
    2. Observe for opportunistic infection
    3. Decrease pain
  2. First-Line
    1. Prednisone 1 mg/kg/day
    2. Methotrexate may be used for Prednisone intolerance
    3. High potency Topical Corticosteroids in localized mild cases
  3. Adjunctive agents (Corticosteroid sparing)
    1. Azathioprine
    2. Mycophenolate mofetil
    3. Leflunomide
    4. Cyclophosphamide
    5. Intravenous Immunoglobulin
    6. Dapsone
    7. Plasmapheresis
    8. Tetracycline or Doxycycline

X. Complications

  1. Secondary Skin Infection

XI. Course

  1. Self-limited condition
  2. Chronic in many cases with exacerbations and remissions
  3. Remits with treatment by 6 years in 50% of cases

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