(CNN)A 25-year-old woman walked into an emergency department in Providence, Rhode Island, complaining of generalized weakness, fatigue, shortness of breath... and an unusual symptom you don't see every day.
She was turning blue. Literally.
Physicians Otis Warren and Benjamin Blackwood wrote about the case in a study published in the New England Journal of Medicine on Thursday.
They attributed her blueness to a numbing agent the woman was using, which deadens nerve endings in the skin.
"She reported having used large amounts of topical benzocaine the night before for a toothache," the two co-authors wrote.