A Blistering Rash With a Diagnostic Sign

A 96-year-old woman presented to the emergency department with a vesicular rash that started 5 weeks earlier. The evolving skin eruptions were pruritic and started on her back. She was not on any medications. Vital signs were normal. No mucosal involvement was observed. Skin examination revealed diffuse skin erosions and multiple areas of tense bullae (Figs 1 and 2). Application of pressure on the bullae resulted in lateral extension to adjacent skin (Video).