Causes of Deviated Nasal Septum and Differentiation of Traumatic vs Non-Traumatic Deviations
Deviated nasal septum arises from either birth trauma, postnatal injury, or developmental factors, and you can differentiate traumatic from non-traumatic causes primarily through timing of onset, history of injury, and specific anatomical patterns on examination.
Causes of Deviated Nasal Septum
Traumatic Causes
Birth Trauma
- Occurs in 0.93-14.3% of newborns, with higher incidence in vaginal deliveries compared to cesarean section 1, 2
- Most commonly seen in infants born head-first, resulting from mechanical pressure during delivery 1
- Presents as anterior cartilaginous dislocation of the nasal septum 2
Postnatal Trauma
- Most common cause in adults: motor vehicle accidents, sports injuries, and altercations 3
- Nasal fracture is the most frequent facial bone injury in adults 3
- Repetitive behaviors like rhinotillexomania (compulsive nose-picking) 4
- Iatrogenic from prior nasal surgery 4
Non-Traumatic Causes
Toxic/Chemical
Infectious
- Bacterial, mycobacterial, and fungal infections (particularly in immunocompromised patients) 4
Inflammatory
Neoplastic
- Primary or secondary tumors involving the septum (carcinomas, sarcomas, hemangiomas, schwannomas) 4
Developmental
Differentiating Traumatic from Non-Traumatic Deviations
Key Historical Features
Traumatic Indicators:
- Acute onset with clear temporal relationship to injury event
- History of nasal fracture, facial trauma, or difficult vaginal delivery (in neonates)
- Immediate or early development of nasal obstruction symptoms
- In newborns: detected within first 3 days of life, associated with head-first delivery 2, 5
Non-Traumatic Indicators:
- Gradual onset of symptoms without precipitating event
- Progressive worsening over months to years
- Associated systemic symptoms (fever, weight loss, constitutional symptoms suggesting inflammatory or infectious etiology)
- History of substance abuse (cocaine, decongestants) 4
- Immunocompromised state suggesting infectious cause 4
Physical Examination Patterns
Traumatic Deviations:
- Specific anatomical configurations: The nose should be analyzed in horizontal thirds (upper bony pyramid, middle dorsal septum/upper lateral cartilages, lower alar cartilages/caudal septum) 6
- Isolated anterior cartilaginous dislocation in newborns 2
- C-shaped or S-shaped deviations with sharp angulations
- Associated external nasal deformity or asymmetry
- Evidence of prior fracture on palpation
- Caudal septal deflection with posterior septal angle displacement 6
Non-Traumatic Deviations:
- Mucosal changes: ulceration, crusting, perforation (suggests inflammatory, infectious, or toxic causes) 4
- Bilateral involvement or diffuse septal thickening
- Granulation tissue or masses
- Septal perforation without trauma history (Wegener, cocaine use, chronic decongestant use) 4
- Smooth, gradual curves rather than sharp angulations
Imaging Characteristics
CT scan findings help distinguish causes:
- Traumatic: Fracture lines, bony displacement, isolated septal deviation without mucosal disease
- Non-traumatic: Mucosal thickening, sinus opacification, bone erosion, soft tissue masses 4
- Severe angular deviations (>15-20 degrees) correlate more strongly with symptoms and may suggest traumatic etiology 7
Age-Specific Considerations
Newborns (0-3 days):
- If deviation detected at birth = birth trauma until proven otherwise 2, 5
- Requires immediate intervention within first 3 days for optimal outcomes 5
Children/Adolescents:
- Consider developmental factors if no trauma history
- Birth trauma effects may persist if untreated 5
Adults:
Clinical Pitfalls to Avoid
- Do not assume all deviations are traumatic - up to 50% of patients with "traumatic" nasal deformity have underlying structural issues that were inadequately addressed 3
- Do not overlook systemic disease - septal perforation or erosion demands workup for Wegener, sarcoidosis, or infectious causes 4
- In newborns, do not delay - intervention after 3 days significantly reduces success rates 5
- Distinguish deviation from asymmetry - asymmetries involve left-right differences in shape/width, while deviations involve positional displacement from midline 6
The key to differentiation lies in obtaining a detailed trauma history, noting the temporal relationship between onset and symptoms, examining for associated mucosal pathology, and recognizing age-specific patterns. When history is equivocal, CT imaging can reveal fracture patterns (traumatic) versus mucosal disease or erosive changes (non-traumatic) 4.