What causes a foul smell in the nasal sinus and how is it treated?

Causes and Treatment of Foul Smell in Nasal Sinus

Foul smell from the nasal sinus is most commonly caused by atrophic rhinitis, chronic sinusitis, foreign bodies, or nasal polyps, and should be treated with nasal hygiene, antibiotics for infection, and addressing the underlying cause through appropriate interventions. 1

Common Causes of Foul Smell in Nasal Sinus

1. Atrophic Rhinitis

• Primary (idiopathic) atrophic rhinitis: Characterized by progressive atrophy of nasal mucosa, nasal crusting, dryness, and fetor (foul odor) 1
• Secondary atrophic rhinitis: Develops from chronic granulomatous disorders, chronic sinusitis, excessive nasal surgery, trauma, or radiation 1
• Bacterial colonization: Common pathogens include Klebsiella ozaenae, Staphylococcus aureus, Proteus mirabilis, and Escherichia coli 1

2. Foreign Bodies

• More common in children but can occur in adults 2, 3
• Presents with unilateral foul-smelling discharge, nasal obstruction, and discomfort 2
• Can lead to rhinoliths (mineralized foreign bodies) that grow in size over time 3
• Particularly concerning with disk batteries, which can cause tissue necrosis within hours 1

3. Chronic Rhinosinusitis

• Can present with nasal congestion, mucopurulent discharge, facial pain/pressure, and reduced sense of smell 1, 4
• May be associated with nasal polyps that contribute to symptoms 1
• Reduced sense of smell can indicate disease severity 4

4. Other Causes

• Rhinitis medicamentosa: From overuse of intranasal decongestants or cocaine 1
• Anatomical abnormalities: Deviated septum, enlarged turbinates, or nasal valve dysfunction 1
• Nasal tumors: Benign or malignant growths that may present with unilateral bleeding and obstruction 1

Diagnostic Approach

1. Initial Assessment

• Determine pattern, chronicity, and seasonality of nasal symptoms 1
• Identify precipitating factors and response to previous medications 1
• Assess for unilateral vs. bilateral symptoms (unilateral symptoms often indicate foreign body or tumor) 1, 2

2. Physical Examination

• Anterior rhinoscopy to visualize the anterior nasal cavity 1
• Nasal endoscopy is essential for:
  • Identifying the site of bleeding or discharge 1
  • Examining the nasal cavity and nasopharynx for unrecognized pathology 1
  • Detecting foreign bodies not visible with anterior rhinoscopy 1
  • Evaluating for nasal polyps or tumors 1

3. Additional Testing

• CT scan of sinuses for suspected chronic sinusitis or structural abnormalities 1
• Objective smell testing using validated tests for olfactory dysfunction 5
• Nasal cultures when bacterial infection is suspected 1

Treatment Approach

1. For Atrophic Rhinitis

• Continuous nasal hygiene is the mainstay of treatment:
  • Intranasal irrigations with saline or sodium bicarbonate solution 1
  • Periodic debridement of crusts when necessary 1
• Antibiotics:
  • Topical antibiotics (e.g., mupirocin) added to lavage solution for purulent secretions 1
  • Systemic antibiotics when acute infection is present 1

2. For Foreign Bodies

• Prompt removal of the foreign body under appropriate visualization 1, 2
• Post-removal care to prevent infection and promote healing 2
• Endoscopic evaluation to ensure complete removal 1

3. For Chronic Rhinosinusitis

• Intranasal corticosteroids (first-line therapy) 4
• Nasal saline irrigation 4
• Systemic corticosteroids for severe cases 4
• Antibiotics when bacterial infection is present 1
• Surgical intervention for refractory cases or when polyps are present 4

4. For Nasal Polyps

• Intranasal corticosteroids to reduce polyp size 1
• Systemic corticosteroids for significant polyp disease 4
• Endoscopic sinus surgery for polyp removal in refractory cases 1
• Biologic therapies (e.g., dupilumab) for severe cases with type 2 inflammation 4

Special Considerations and Pitfalls

• Unilateral symptoms: Always warrant thorough investigation for foreign bodies or tumors 1, 2
• Persistent symptoms: Require nasal endoscopy even when a bleeding site is identified in Kiesselbach's plexus 1
• Rhinitis medicamentosa: Requires cessation of the offending topical decongestant 1
• Disk batteries: Require emergency removal due to rapid tissue damage 1
• Olfactory dysfunction: Often underreported by patients but significantly impacts quality of life 4

Follow-up Recommendations

• Regular nasal hygiene for patients with atrophic rhinitis 1
• Monitoring for recurrence of symptoms after foreign body removal 2
• Assessment of smell improvement as an indicator of successful treatment 4
• Endoscopic evaluation for persistent or recurrent symptoms 1

By systematically addressing the underlying cause of the foul smell and implementing appropriate treatment strategies, most patients can achieve significant symptom improvement and better quality of life.