The Diabetic Nose: A Narrative Review of Rhinologic Involvement in Diabetes (1973-2025).

Area of Science:

• Otorhinolaryngology
• Endocrinology
• Immunology

Background:

• Diabetes mellitus (DM) is increasingly recognized to affect upper airway function via vascular, inflammatory, and neuro-sensory pathways.
• The sinonasal mucosa is a potential early site for diabetic microangiopathy and immune-metabolic dysregulation.
• Understanding the link between DM and sinonasal disease is crucial for patient care.

Purpose of the Study:

• To review current evidence on rhinologic manifestations in diabetes mellitus.
• To focus on chronic rhinosinusitis, olfactory dysfunction, and other nasal disorders.
• To identify pathophysiologic and clinical patterns connecting diabetes and sinonasal conditions.

Main Methods:

• Systematic review of existing literature.
• Analysis of studies investigating diabetes mellitus and sinonasal diseases.
• Synthesis of evidence on immune-metabolic, vascular, and neuro-sensory mechanisms.

Main Results:

• Diabetes mellitus, especially type 2, correlates with increased susceptibility to chronic rhinosinusitis with nasal polyps (CRSwNP) and shifts the sinonasal microbiome.
• Diabetic patients experience more frequent and severe olfactory dysfunction due to inflammation, vascular issues, and insulin resistance.
• Other manifestations include epistaxis, impaired mucociliary clearance, and chronic cough; allergic rhinitis may be inversely related, particularly with DPP-4 inhibitor use.

Conclusions:

• Diabetes influences rhinologic health through immune-metabolic, vascular, and epithelial pathways, affecting disease susceptibility and neurosensory function.
• Further research is needed to differentiate type-specific mechanisms and identify biomarkers for personalized management.
• Precision-based approaches are essential for assessing and managing rhinologic issues in diabetic patients.