What is the appropriate management for a 78-year-old female patient presenting with acute onset of bullous lesions over the last 2 days?

Acute Bullous Lesions in a 78-Year-Old Patient

This patient most likely has bullous pemphigoid and requires immediate dermatology consultation with skin biopsy for direct immunofluorescence to confirm diagnosis, followed by initiation of superpotent topical corticosteroids (clobetasol 0.05%) for limited disease or systemic corticosteroids (prednisone 0.5-0.75 mg/kg/day, approximately 30-50 mg daily) for widespread involvement. 1

Immediate Diagnostic Workup

Clinical Assessment

• Document distribution and extent of lesions: Look specifically for tense bullae on flexural surfaces (limbs, inner thighs, abdomen), presence or absence of mucosal involvement, and whether lesions arise from erythematous or normal-appearing skin 1
• Assess severity: Count the number of new blisters daily and estimate body surface area involvement 1
• Obtain detailed medication history: Review all drugs started in the past 1-6 months, particularly diuretics (furosemide, spironolactone), gliptins, and psycholeptic drugs, as these commonly trigger drug-induced bullous pemphigoid 1, 2
• Evaluate comorbidities: Specifically inquire about neurological and cardiovascular diseases, which are associated with bullous pemphigoid 1

Essential Laboratory Studies

• Skin biopsy for histopathology: Take from an early intact bulla on erythematous skin; expect subepidermal bullae with eosinophils and/or neutrophils 1
• Direct immunofluorescence (DIF): This is the most critical diagnostic test—obtain from perilesional (non-blistered) skin adjacent to a blister; positive linear IgG and/or C3 deposits along the dermoepidermal junction confirms bullous pemphigoid 1
• Serum autoantibodies: BP180 ELISA is more sensitive than BP230 ELISA and can help confirm diagnosis and monitor disease activity 1

Clinical Diagnostic Criteria

If three of these four criteria are present with positive DIF, bullous pemphigoid diagnosis is highly specific: 1

• Age >70 years
• Absence of atrophic scars
• Absence of mucosal involvement
• Absence of predominant bullous lesions on neck and head

Treatment Algorithm Based on Disease Severity

Limited Disease (<10% BSA, Few Lesions)

• First-line: Superpotent topical corticosteroids (clobetasol 0.05% or betamethasone dipropionate 0.05%) applied twice daily to affected areas 1
• Local wound care: Apply plain petrolatum ointment with bandages to any erosions 1
• Reassess every 3 days for progression or improvement 1
• Low threshold to escalate: If no improvement within 3-7 days or if new lesions develop, initiate systemic therapy 1

Moderate to Extensive Disease (>10% BSA or Symptomatic)

• Systemic corticosteroids: Prednisone 0.5-0.75 mg/kg/day (approximately 30-50 mg daily for a 70 kg patient) 1
• Critical dosing consideration: Doses >0.75 mg/kg/day (>52.5 mg daily) provide no additional benefit and significantly increase mortality risk in elderly patients 1
• Taper schedule: Once disease is controlled (typically 1-4 weeks), taper gradually over at least 4 weeks 1
• Maintenance approach: Accept occasional blisters during tapering rather than increasing dose, to avoid overtreatment 1

Severe Disease (>30% BSA, Mucosal Involvement, or Systemic Symptoms)

• Consider hospitalization for close monitoring 1
• IV methylprednisolone 1-2 mg/kg/day, then convert to oral steroids when appropriate 1
• Early consideration of steroid-sparing agents: IVIG or rituximab may be appropriate to avoid prolonged high-dose corticosteroids 1, 3

Critical Management Pitfalls

Drug-Induced Bullous Pemphigoid

• Approximately 50% of drug-induced cases persist despite drug withdrawal and require standard bullous pemphigoid treatment 2
• Do not delay treatment while waiting for drug withdrawal to take effect 2
• Most common triggers: Loop diuretics, gliptins, spironolactone, and neuroleptics have the strongest evidence 2

Steroid-Related Mortality Risk

• High-dose systemic corticosteroids (>40 mg prednisone daily) are associated with significantly higher first-year mortality in elderly patients with bullous pemphigoid 1
• This mortality risk often exceeds the risk from the disease itself in frail elderly patients 1
• Use minimum effective dose: Start at 0.5 mg/kg/day rather than higher doses 1

Differential Diagnosis Considerations

• Rule out infections first: Viral (especially varicella in adults) and bacterial infections must be excluded before starting immunosuppression 1
• Other autoimmune bullous diseases: Mucous membrane pemphigoid, epidermolysis bullosa acquisita, and linear IgA disease require DIF and salt-split indirect immunofluorescence to differentiate 1
• Bullous pyoderma gangrenosum: Consider if lesions are rapidly progressive and painful, especially if patient has hematologic malignancy history 4

Monitoring and Follow-Up

Initial Phase (First 3 Months)

• Follow-up every 2 weeks to assess treatment response and adjust therapy 2
• Monitor for steroid side effects: Hyperglycemia, hypertension, infections, and osteoporosis 1
• Serial photography can help objectively track disease progression 1

Maintenance Phase (After 3 Months)

• Monthly follow-up visits for the next 3 months 2
• Gradual dose reduction: Taper steroids whenever disease has been well controlled for ≥1 month 1
• Disease typically remits within 5 years, so long-term immunosuppression is usually not necessary 1

Refractory Disease

• Consider steroid-sparing agents if unable to taper below 10-15 mg prednisone daily or if significant steroid side effects develop 3
• IVIG is third-line therapy for severe, unstable, steroid-dependent disease where other immunosuppressants have failed 3
• Azathioprine can reduce total steroid dose by approximately 45%, but avoid concurrent allopurinol due to severe myelosuppression risk 1, 5