A 37-year-old woman presents to the ED complaining of a painful lump on the back of her head. It started about 10 days earlier as a small bump that she noticed while bathing.
Gradually, it became bigger and more painful. She denies any trauma to the area except for some initial scratching. She has had no fevers or chills, and has no other lesions on her body.
What is your diagnosis? See p. 24.