A. Aspirate the bullae with a sterile needle and cover with a clean dressing
The key to the correct diagnosis was recognition of spontaneous blistering on noninflamed skin in a patient with diabetes. The long-standing nature of the patient’s diabetes was supported by the incidental finding of diabetic dermopathy, characterized by hyperpigmented macules and patches on the anterior lower legs. A skin biopsy (choice B) is not needed to make the diagnosis in the appropriate clinical context and would likely show nonspecific features, such as subepidermal blister formation with minimal inflammation and negative direct immunofluorescence.1,2 Oral prednisone (choice C) is not recommended because the diagnosis of bullous pemphigoid is unlikely with bullae on a single distal extremity, and prednisone might worsen the patient’s hyperglycemia. Choice D (oral cephalexin) is incorrect because the lack of surrounding erythema, warmth, tenderness, and serous crusting make infection unlikely.