What are the key aspects to cover in a presentation on bullous pemphigoid?

Key Aspects for a Presentation on Bullous Pemphigoid

A comprehensive presentation on bullous pemphigoid should cover disease definition, epidemiology, pathophysiology, clinical features, diagnosis, treatment options, and monitoring parameters as defined by international guidelines. 1

Definition and Epidemiology

• Bullous pemphigoid (BP) is an acquired autoimmune subepidermal bullous disease with autoantibodies directed against components of the basement membrane zone 2
• Most common autoimmune blistering disease in Western countries with incidence of 6-7 cases per million population per year 2
• Primarily affects elderly patients (>70 years) but can occur in younger patients and children 2
• Equal sex distribution 2
• Significant associations with neurological disorders (dementia, Parkinson's disease, cerebrovascular disease) and cardiovascular diseases 1

Pathophysiology

• Autoantibodies (mainly IgG) target BP180 and BP230 antigens in the hemidesmosome adhesion complex 2
• Antigen-antibody interaction leads to complement activation, inflammatory cell recruitment, and subsequent subepidermal blister formation 2
• BP180 ELISA titers correlate with disease activity and can be used to monitor treatment response 1

Clinical Features

• Tense blisters arising on erythematous or normal-appearing skin 2
• Pruritus varies from none to intense and may precede blisters by weeks, months, or years 2
• Urticarial or eczematous prodromal phase common 2
• Mucosal involvement in 10-30% of patients, primarily oral mucosa 2
• Clinical variants include classic (bullous), localized, nodular, vegetating, erythrodermic, erosive, childhood and drug-induced forms 3

Diagnostic Approach

1. Clinical assessment

   • Evaluate for tense bullae, urticarial plaques, and pruritus 4

2. Histopathology

   • Skin biopsy from early bulla on erythematous skin
   • Look for subepidermal bullae with eosinophils/neutrophils 1

3. Direct Immunofluorescence (DIF)

   • Essential for diagnosis (93% positivity rate)
   • Perilesional skin shows linear deposits of IgG and/or C3 along dermoepidermal junction 1

4. Serological Tests

   • ELISA for anti-BP180 and anti-BP230 antibodies
   • Indirect immunofluorescence on salt-split skin differentiates BP from epidermolysis bullosa acquisita and cicatricial pemphigoid 2

5. Pre-treatment Laboratory Tests

   • Complete blood count, ESR, CRP
   • Renal and liver function tests
   • Serology for hepatitis B, C, and HIV
   • Glucose-6-phosphate dehydrogenase
   • Thiopurine methyltransferase 1

Disease Severity Assessment

• Bullous Pemphigoid Disease Area Index (BPDAI) - standardized scoring system for disease extent and activity 2
• Evaluates skin activity (blisters/erosions, urticarial/erythematous lesions) and damage (post-inflammatory hyperpigmentation) 2

Treatment Algorithm

1. Mild Localized Disease

   • First-line: Superpotent topical corticosteroids (clobetasol propionate 0.05%) applied twice daily until lesions heal, then continue for 2 weeks after healing before tapering 1

2. Generalized Disease

   • First-line: Oral corticosteroids (prednisolone) at 0.5-0.75 mg/kg/day 1
   • Higher doses provide no additional benefit 1

3. Second-line Options

   • Tetracycline + nicotinamide
   • Dapsone (after G6PD testing)
   • Topical immunomodulators (tacrolimus) 1

4. Third-line Options for Resistant Cases

   • Anti-CD20 (rituximab) or anti-IgE (omalizumab) monoclonal antibodies
   • Intravenous immunoglobulins
   • Immunoadsorption
   • Plasma exchange
   • Cyclophosphamide 1
   • Newer biologics: dupilumab and JAK inhibitors 5

Monitoring and Disease Control Parameters

• Early observation endpoints 2

  • Baseline: Day treatment starts
  • Control of disease activity: When new lesions cease to form and established lesions begin to heal
  • End of consolidation phase: No new lesions for minimum 2 weeks and ~80% of lesions healed

• Late observation endpoints 2

  • Complete remission on minimal therapy: No new/established lesions while on minimal therapy for ≥2 months
  • Complete remission off therapy: No new/established lesions while off all BP therapy for ≥2 months
  • Relapse/flare: ≥3 new lesions/month that don't heal within 1 week

• Follow-up schedule 1

  • Every 2 weeks until disease control
  • Monthly for next 3 months
  • Every 2 months thereafter until treatment stopped

Special Considerations

• Ocular involvement: Requires urgent ophthalmology consultation 1
• Laryngeal involvement: Requires ENT evaluation 1
• Pregnancy management: Use topical corticosteroids, lowest effective dose systemic corticosteroids, or azathioprine if steroid-sparing agent needed 1
• Immune checkpoint inhibitor-associated BP: May require discontinuation of immunotherapy 1

Prognosis

• Generally self-limiting disease that remits within 5 years 2
• Mortality rates vary between 6-41% in modern era (compared to 24% before oral corticosteroids) 2
• Elderly patients at high risk for adverse drug reactions and side effects 2

This structured approach provides a comprehensive framework for presenting bullous pemphigoid, covering all essential aspects from pathophysiology to management based on current international guidelines.