The etiology of nasal septal perforations can be classified into the following 4 main categories: traumatic, iatrogenic, inflammatory/malignant, and cocaine use. Most traumatic or iatrogenic perforations result from mucosal lacerations on corresponding sides of the septum with exposure of the underlying cartilage or from a fracture of the cartilaginous septum. Perforation occurs because the cartilage relies upon the overlying mucoperichondrium for its blood supply and nutrients. Traumatic injuries may be self-induced from nose picking or may result from facial trauma. Iatrogenic causes include nasal surgical procedures (prior septal surgery is the most common cause of septal perforations) and nasal intubation or nasogastric tube placement. Septal hematoma, if not identified and treated early, also may result in perforation.
Infectious and inflammatory etiologies, including tuberculosis, syphilis, Wegener granulomatosis, and sarcoidosis, always should be considered in the differential diagnosis.
Cocaine use is widespread and affects all social classes. Patients present often with large and expanding perforations. Primary mechanisms of injury from cocaine use are 2-fold. First, vasoconstrictive properties lead to decreased nutrients to the underlying cartilage. Second, illicit cocaine contains adulterants that act as chemical irritants, damaging the nasal mucosa. Nasal obstruction often accompanying perforation probably will not be improved after repair due to physiologic changes in the mucosa from chronic abuse. These patients pose a particularly difficult problem.
Numerous inhalation irritants also have been implicated in causing septal perforations, including chromic or sulfuric acid fumes, glass dust, mercurials, and phosphorous.
For more information, check this excellent article by Drs.Romo and Liu.