An 80-year-old woman is evaluated for blisters that have developed on both feet over the past week. The patient lives in a nursing home due to dementia but has no other chronic medical conditions and takes no medication. Vital signs are within normal limits. There are no oral lesions. Examination findings are shown in the exhibit.
Which of the following is most likely involved in the pathogenesis of this patient's condition?

Question

An 80-year-old woman is evaluated for blisters that have developed on both feet over the past week.  The patient lives in a nursing home due to dementia but has no other chronic medical conditions and takes no medication.  Vital signs are within normal limits.  There are no oral lesions.  Examination findings are shown in the exhibit.  
Which of the following is most likely involved in the pathogenesis of this patient's condition?

Quizplus · Accepted Answer

11ec160b_38f0_f72e_9249_870052d31689_MD0001_00 This elderly patient has the typical features of bullous pemphigoid (BP), an autoimmune blistering disease. BP most commonly affects individuals age >60 and is more common in those with neurologic disorders (eg, Alzheimer dementia). As in this patient, bullae are typically tense and have erythematous or normal-appearing bases. Lesion distribution can be localized or diffuse, involving the trunk and extremities; mucosal involvement is rare. BP is caused by antibodies against hemidesmosomes along the basement membrane of the dermal-epidermal junction. These autoantibodies result in a destructive inflammatory cascade that causes the entire epidermis to separate from the dermis, forming subepidermal blisters. Immunofluorescence shows IgG and/or C3 deposits in a linear pattern along the basement membrane. (Choice A) Deposition of IgA-containing immune complexes within the dermal papillae is characteristic of dermatitis herpetiformis, an autoimmune dermatitis associated with gluten sensitivity. It typically presents as groups of pruritic papulovesicles on the extensor extremities, scalp, back, and buttocks in patients age 40-50. (Choice C) Deposition of IgG within the epidermal layer at the intercellular level is characteristic of pemphigus vulgaris, which typically affects patients age 40-60 and presents with flaccid, not tense, blisters that easily rupture, forming erosions. Absent in this patient, mucosal involvement is almost always present in pemphigus vulgaris. (Choice D) Disrupted assembly of keratin into monofilaments describes epidermolysis bullosa simplex, an autosomal dominant condition presenting with blisters in areas of high friction (eg, hands, feet, knees). Unlike BP, the condition typically presents during infancy through early adulthood. (Choice E) Increased vascular permeability due to gaps between endothelial cells is characteristic of blisters associated with partial-thickness burn wounds or localized inflammation (eg, poison ivy). Educational objective: Bullous pemphigoid is an autoimmune blistering disease that typically occurs in patients >60. It presents with tense bullae with rare mucosal involvement. Autoantibodies against hemidesmosomes create subepidermal cleavage. Immunofluorescence shows linear deposition of IgG and/or C3 along the basement membrane. __________ References: Bullous pemphigoid. (http://www.ncbi.nlm.nih.gov/pubmed/31090818)

An 80-Year-Old Woman Is Evaluated for Blisters That Have Developed