A 12-year-old Hispanic girl presents with an 8-day history of recurrent blisters on both legs. She initially thought that it was due to a mosquito bite but became concerned when she began to develop larger blisters, some of which appeared pus-filled.
On examination, there were round excoriated plaques with a collarette of scale. There was one intact blister filled with clear and purulent fluid.
A skin biopsy demonstrates a subcorneal blister with an inflammatory infiltrate in the dermis consisting of neutrophils. Gram-positive cocci can be seen in the superficial epidermis.
What is the diagnosis?