Can a deviated nasal septum (DNS) cause allergic rhinitis?

Deviated Nasal Septum and Allergic Rhinitis: Relationship and Management

A deviated nasal septum does not cause allergic rhinitis, but it can exacerbate symptoms and complicate management of allergic rhinitis. According to clinical guidelines, a deviated nasal septum is classified as a structural/mechanical factor that may mimic symptoms of rhinitis rather than a direct cause of allergic rhinitis 1.

Relationship Between Deviated Nasal Septum and Allergic Rhinitis

• Deviated nasal septum (DNS) is listed in clinical guidelines as a condition that may mimic symptoms of rhinitis, not as a cause of allergic rhinitis 1
• Approximately 80% of the general population has an off-center nasal septum, but only about 26% have clinically significant deviation causing symptoms 2
• Anterior septal deviation is more clinically significant than posterior deviation as it affects the nasal valve area responsible for more than 2/3 of airflow resistance 2
• DNS can contribute to nasal obstruction symptoms that may be confused with or exacerbate allergic rhinitis, but it does not trigger the immunological mechanisms that cause allergic rhinitis 1

Differential Diagnosis

• Rhinitis should be classified by etiology as allergic or nonallergic and differentiated from conditions that mimic symptoms of rhinitis 1
• Allergic rhinitis is characterized by an IgE-mediated immune response to specific allergens, while DNS is a structural abnormality 1
• Conditions that may mimic symptoms of rhinitis include nasal polyps, deviated septum, adenoidal hypertrophy, and other structural/mechanical factors 1
• Mixed rhinitis (combined allergic and nonallergic rhinitis) is noted in approximately 44% to 87% of patients with allergic rhinitis and is more common than either pure allergic rhinitis or nonallergic rhinitis 1

Clinical Implications

• Patients with both DNS and allergic rhinitis may have more complex nasal obstruction that is less responsive to medical management alone 3
• Studies show that patients with both DNS and allergic rhinitis have less improvement in nasal airflow after septoplasty compared to patients with DNS alone 4
• The presence of a slightly deviated nasal septum does not significantly affect the outcome of treatment for allergic rhinitis in some studies 5
• Patients with DNS and refractory allergic rhinitis may benefit from surgical intervention, but improvement in subjective performance parameters may not be significantly different between septoplasty alone versus septoplasty with turbinate reduction 3

Management Approach

• Medical management of allergic rhinitis should be the first priority before considering surgical intervention for DNS 4
• A complete medical management trial should include regular use of intranasal corticosteroids, saline irrigations, appropriate antibiotics for bacterial sinusitis if present, and treatment of any underlying allergic component 6, 2
• Septoplasty should only be considered medically necessary when there is septal deviation causing continuous nasal airway obstruction that has not responded to at least 4 weeks of appropriate medical therapy 6, 2
• Patients with both DNS and allergic rhinitis should be counseled that they may have less improvement after septoplasty compared to patients without allergic rhinitis 4

Surgical Considerations

• If medical therapy fails after appropriate duration (4+ weeks), septoplasty may be indicated for patients with significant nasal obstruction due to DNS 2
• Adding bilateral inferior turbinoplasty to septoplasty in patients with DNS and allergic rhinitis can provide significant improvement in nasal obstruction symptoms, though subjective performance parameters may not show significant differences compared to septoplasty alone 3
• The American Academy of Otolaryngology recommends that comprehensive medical management attempts should be documented before considering surgical intervention 2
• Surgery may play a beneficial role in improving nasal airflow and allowing for more effective delivery of topical medications for allergic rhinitis 1

Common Pitfalls and Caveats

• Not considering that nasal congestion may be due to allergic rhinitis, which should be treated medically first before attributing symptoms solely to DNS 6
• Assuming that correcting DNS will resolve allergic rhinitis symptoms without addressing the underlying allergic component 4
• Failing to provide adequate medical management of allergic rhinitis before considering surgical intervention 6, 2
• Not recognizing that patients with both DNS and allergic rhinitis may have less satisfactory outcomes after septoplasty compared to patients with DNS alone 4