excerpt:
The mucous membrane of both sides of the septum (the cartilage that separates the nostrils) can be damaged by decreased blood supply, along with drying, crusting, and nose picking. This results in a perforation or hole in the septum with more crusting, foul secretions, nosebleeds, and whistling with nasal breathing, the so-called coke nose.
(Off topic. Couldn't resist.)