Snapshot A 80-year-old man presents with a 2-week history of severe pruritus and eczema. His past medical history includes atopic dermatitis, thyroid disease, and multiple sclerosis. On physical exam, he has dozens of 1-2 cm tense bullae and several erosions over his upper and lower extremities. His oral mucosa is not involved. Nikolsky sign is negative. A skin biopsy is taken and anti-BP180 is detected in his blood. A potent topical steroid is prescribed. Introduction Clinical definition bullous pemphigoid (BP) is an autoimmune blistering disorder characterized by bullae (> 1 cm large, fluid-containing blister) and severe pruritus Associated conditions drug use loop diuretics metformin neuroleptics neurologic conditions multiple sclerosis dementia Parkinson disease Epidemiology Demographics more common in those > 70 years of age rarely in infants ETIOLOGY 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 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 does not easily rupture in adults typically symmetrically distributed on trunks and extremities in infants palms and soles more commonly affected 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 Based primarily on clinical presentation and observation Skin biopsy shows subepidermal blisters which are often with eosinophil-rich infiltrates Immunofluorescence shows a linear band of immunoglobulins targeting hemidesmosomes and complement at epidermal-dermal junction Complete blood count (CBC) may show eosinophilia 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 Prognosis Can resolve spontaneously Often recurs