What causes inferior turbinate hypertrophy in adults?

Causes of Inferior Turbinate Hypertrophy

Inferior turbinate hypertrophy results from chronic inflammation of the turbinate mucosa leading to mucosal edema, venous engorgement, and eventual structural hypertrophy of both mucosal and bony components, triggered by multiple factors including allergic rhinitis, compensatory mechanisms from septal deviation, non-allergic rhinitis, and chronic irritant exposure. 1

Primary Etiologic Mechanisms

Allergic Inflammation

• Chronic allergen exposure triggers inflammatory mediators that cause mucosal edema, venous engorgement, and progressive structural hypertrophy of both mucosal and bony turbinate components 1
• However, radiological studies demonstrate that the degree of inferior turbinate hypertrophy shows no significant difference between patients with and without allergic rhinitis, suggesting allergy may not be the primary driver of structural hypertrophy 2

Compensatory Hypertrophy from Septal Deviation

• Compensatory turbinate hypertrophy commonly develops on the side opposite to septal deviation, and may be bilateral with S-shaped deviation patterns 3
• The contralateral side to septal deviation consistently shows larger turbinate width than the deviated side, particularly in the anterior portion of the inferior turbinate 2
• This compensatory mechanism occurs regardless of allergic status 2

Non-Allergic Rhinitis

• Non-allergic rhinitis with chronic inflammation leads to inferior turbinate hypertrophy through similar mucosal and submucosal changes as allergic mechanisms 4
• Chronic non-specific inflammation from infections or irritants causes infiltration by inflammatory cells in both mucosa and bony tissue 5

Anatomical Components of Hypertrophy

Mucosal vs. Bony Hypertrophy

• The surgeon must assess the contribution of turbinate mucosal hypertrophy versus the position and degree of bony hypertrophy, as this determines appropriate treatment selection 6
• Mucosal hypertrophy can be differentiated from bony hypertrophy by applying topical decongestant and observing reduction of turbinate mucosa edema 1
• Combined mucosal and bony hypertrophy represents the most common presentation requiring surgical intervention 1

Contributing Factors

Chronic Irritant Exposure

• Environmental irritants and chronic nasal inflammation contribute to progressive turbinate enlargement through sustained mucosal inflammation 1
• Rhinitis medicamentosa from chronic topical decongestant use (such as Afrin) can worsen turbinate hypertrophy 1

Vasomotor Dysfunction

• Pathologic enlargement can result from dysregulation of turbinate vascular tone and autonomic control mechanisms 7
• Venous engorgement from vascular dysfunction contributes to both acute and chronic turbinate enlargement 1

Clinical Significance

• Approximately 20% of the population experiences chronic nasal obstruction caused by turbinate hypertrophy, which often requires surgical intervention when medical management fails 6, 1
• The anterior part of the inferior turbinate shows the most significant hypertrophy and contributes most to nasal obstruction, as this region affects the nasal valve area responsible for more than 2/3 of airflow resistance 3, 2
• Turbinate hypertrophy can persist and cause nasal obstruction even after properly performed septorhinoplasty correcting septal deflection 7