Nasal septum perforation occurs in all the following except -
Causes of septal perforation are : -

1) Trauma
2) Iatrogenic : - Nasal surgery, nasal intubation or nasogastric tube placement

Chronic inflammation (Wegener's granulomatosis, Syphilis, T.B. Leprosy, atrophic rhinitis, Sarcoidosis)
Nasal myiasis
Rhinolith or neglected foreign body.
As a complication of septal abscess or hematoma, if drainage is delayed.
Poisons (cocaine, topical steroids and decongestants)
Tumors of septum e.g., chondrosarcoma, granuloma
Tuberculosis
Nasal surgery
Syphilis
Rhinosporidiosis