What is the likely diagnosis and recommended management for a patient with multiple depigmented and hypopigmented facial plaques, tense bullae, and healing scars on both hands?

Likely Diagnosis: Bullous Pemphigoid

This patient most likely has bullous pemphigoid (BP), an autoimmune subepidermal blistering disease characterized by tense bullae, pruritic erythematous plaques, and depigmented/hypopigmented healing scars, particularly affecting the hands and face. 1

Clinical Features Supporting BP Diagnosis

The presentation matches the classical and atypical forms of BP:

• Tense bullae on bilateral hands are characteristic of BP, which typically affects flexural surfaces of limbs, inner thighs, abdomen, and extremities 1
• Healing scars with depigmentation/hypopigmentation occur as post-inflammatory changes after bullae resolve, though BP classically causes minimal atrophic scarring compared to other blistering diseases 1
• Multiple facial plaques (depigmented and hypopigmented) represent either nonbullous BP variants (urticarial, eczematous lesions) or post-inflammatory pigmentary changes from resolved bullae 1
• Symmetric distribution is typical of BP, distinguishing it from segmental or localized variants 1

Critical Diagnostic Workup

Direct immunofluorescence (DIF) microscopy is the most critical diagnostic test and must show linear IgG and/or C3 deposits along the dermoepidermal junction. 1

Essential Laboratory Tests:

• Skin biopsy for histopathology from an early bullae on erythematous skin showing subepidermal bullae with eosinophils and/or neutrophils 1
• Perilesional skin biopsy for DIF (not from blistered skin) demonstrating linear basement membrane zone deposits 1
• Serological testing with ELISA for anti-BP180 and/or anti-BP230 IgG autoantibodies to confirm diagnosis 1
• Indirect immunofluorescence on NaCl-separated normal human skin to detect circulating antibasement membrane antibodies 1

Clinical Diagnostic Criteria:

When three of four criteria are present with positive DIF, BP diagnosis has high specificity: age >70 years, absence of atrophic scars, absence of mucosal involvement, absence of predominant neck/head bullous lesions 1

Differential Diagnosis Considerations

Epidermolysis bullosa acquisita (EBA) must be excluded as it presents with skin fragility, bullae, erosions, and milia in trauma areas with similar immunofluorescence patterns but targets type VII collagen rather than BP180/BP230 2

• EBA shows dermal-side fluorescence on salt-split skin IIF, while BP shows epidermal-side fluorescence 2
• Type IV collagen mapping helps distinguish BP from EBA 3

Linear IgA bullous dermatosis can coexist with BP and should be considered if severe mucosal involvement is present 4

Management Algorithm

Initial Assessment:

• Document disease extent using Bullous Pemphigoid Disease Area Index (BPDAI) or daily blister count 1
• Evaluate general condition with Karnofsky performance status scale, particularly important in elderly patients 1
• Screen for comorbidities: thyroid function tests (autoimmune thyroid disease occurs in 34% of autoimmune blistering patients), cardiovascular disease, neurological conditions 1, 5
• Review medications from past 1-6 months for potential triggers (diuretics, psycholeptic drugs with aliphatic side chains) 1

Treatment Based on Disease Extent:

For localized disease (face and hands):

• Potent topical corticosteroids (clobetasol propionate) limited to 2-month trials to avoid skin atrophy 1
• Topical calcineurin inhibitors (tacrolimus, pimecrolimus) as steroid-sparing alternatives with better safety profiles 5

For widespread disease:

• Narrowband UVB phototherapy is preferred over PUVA due to greater efficacy 1, 5
• Systemic corticosteroids (prednisone ≤0.1 mg/kg/day as minimal therapy) with immunosuppressants for severe cases 1, 6

Treatment Goals and Monitoring:

• Disease control is achieved when new lesions cease forming and established lesions begin healing 1
• End of consolidation phase occurs when no new lesions appear for ≥2 weeks and 80% of lesions have healed 1
• Monitor for relapse/flare: appearance of ≥3 new lesions per month that don't heal spontaneously within 1 week 1

Common Pitfalls to Avoid

• Failing to perform DIF is the most critical error, as DIF positivity is essential for BP diagnosis 1
• Prolonged potent topical steroid use beyond 2 months causes skin atrophy 5
• Missing thyroid screening overlooks a treatable autoimmune comorbidity present in one-third of patients 5
• Confusing post-inflammatory hypopigmentation with vitiligo—BP healing produces temporary pigmentary changes, not permanent depigmentation 7
• Overlooking psychological impact of visible facial lesions and scarring, which significantly impairs quality of life 5

Multidisciplinary Management Team

Coordinate care with: dermatologist familiar with BP (preferably at referral center), general practitioner/geriatrician for comorbidity management, specialized nurse for elderly care, dietician for nutritional support in extensive disease 1