Saturday, November 8, 2014

A 67-year-old man presents with complaints of diffuse rash with blistering

A 67-year-old man presents with complaints of diffuse rash with blistering. The lesions began as pruritic plaques distributed on the trunk and abdomen.

Lesions are now appearing on the flexor surfaces of the arms. Some of the lesions have developed into tense blisters that rupture. As the lesions have healed, no scarring is present. A photo of the patient’s rash is shown in Figure .

What would be the expected finding on biopsy of the lesion?

A. Cell surface deposition of IgG on keratinocytes
B. Cell surface deposition of IgG and C3 on keratinocytes
C. Granular deposits of IgA in dermal papillae
D. Linear band deposition of IgA in the epidermal basement membrane zone
E. Linear band deposition of IgG and/or C3 in the epidermal basement membrane zone

The answer is E.
Bullous pemphigoid is an autoimmune skin disease associated with the development of tense vesicles and bullae on erythematous bases. The disease is more common in elderly individuals and typically begins as urticarial plaques that are located on the lower abdomen, groin, and flexor surfaces of the extremities.

These lesions often evolve to tense bullae on erythematous or normal-appearing skin. Oral mucosal
lesions can occur, and pruritus is variable from none to severe. The blisters often rupture with secondary erosions and crusting. Without secondary trauma, these lesions will heal without scarring. Biopsy of early lesions shows subepidermal blisters with a variable inflammatory infiltrate. Lesions on an erythematous base demonstrate eosinophilic infiltrates, whereas lesions on normal skin have minimal perivascular infiltrate only.

Direct immunofluorescence shows linear deposits of IgG and C3 along the epidermal basement membranes. In about 70% of individuals, autoantibodies can be found that bind to the epidermal basement membrane. The disease tends to be chronic with relapses and remissions over a period of months to years. The treatment of choice is systemic glucocorticoids
at doses of prednisone equivalent to 0.75–1 mg/kg daily.


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