A 65-year-old female presents to the emergency department with a chief complaint of a severe rash. The rash has been present for two weeks on her arms, neck, and scalp. It began while she was sitting on her porch one afternoon. She denies any associated fevers, chills, headache, or muscle ache. She denies any exposure to pets, new soaps, detergents, or lotions, and she denies recent travel.