Bullous Pemphigoid

Snapshot

• A 75-year-old woman living in a nursing home presents with a 1-month history of severe pruritus. She reports having unrelenting pruritis with a pink rash over her trunk and extremities. Though she tried multiple lotions, the pruritus does not improve. Approximately 2 days ago, she also noticed some blisters on her body. She has never had rashes like this before. On physical exam, she has several 1-3 cm tense bullae on her abdomen and upper arms. Nikolsky sign is negative. A skin biopsy is taken and sent for immunofluorescence.

Introduction

• Clinical definition
  • bullous pemphigoid (BP) is an autoimmune blistering disorder characterized by bullae (> 1 cm large, fluid-containing blister) and severe pruritus   
• Epidemiology
  • demographics
    • more common in those > 70 years of age
• Pathogenesis
  • auto-antibodies (IgG) against hemidesmosomes in the epidermal-dermal junction
    • antibodies are below the epidermis
  • main autoantigens are BP180 and BP230
  • this activates complement and inflammatory reaction which cause epidermal-dermal splitting
• Associated conditions
  • drug use
    • loop diuretics
    • metformin
    • neuroleptics
  • neurologic conditions
    • multiple sclerosis
    • dementia
    • Parkinson disease
• Prognosis
  • can resolve spontaneously
• often recurs

Presentation

• Symptoms
  • severe pruritus
  • may have history of eczematous or urticarial lesions before bullae formation
• Physical exam
  • tense bullae with clear exudate
    • may be hemorrhagic
    • typically symmetrically distributed on trunks and extremities
  • spares mucous membranes
  • negative Nikolsky sign
    • cannot cause separation, blister formation, or blister extension with blunt pressure or lateral traction (dragging finger on skin)
• may have vesicles

Studies

• Labs
  • autoantibodies in serum detected with enzyme-linked immunosorbent assay (ELISA)
    • for monitoring disease activity
    • anti-BP180 antibodies
    • anti-BP230 antibodies
• Histology
  • subepidermal blister with eosinophils
  • direct immunofluorescence
• linear pattern of IgG and C3 deposition along the epidermal-dermal junction

Differential

• Pemphigus vulgaris 
  • more severe than BP
  • affects mucous membranes
• positive Nikolsky sign

Treatment

• Conservative
  • discontinue new medications
    • indications
      • if BP is suspected to be a drug reaction
  • wound care
    • indications
      • all patients
    • antiseptic care for erosions
• Medical
  • topical corticosteroids
    • indications
      • first-line treatment
      • often used with systemic treatments
    • drugs
      • clobetasol
  • prednisone
    • indications
      • for widespread disease or if topical steroids are not feasible
  • steroid-sparing immunosuppressant
    • indications
      • for those contraindicated to steroids
    • drugs
• azathioprine

Complications

• Skin and soft tissue bacterial infection of open lesions